/* Data flow analysis for GNU compiler.
- Copyright (C) 1987, 88, 92-96, 1997 Free Software Foundation, Inc.
+ Copyright (C) 1987, 88, 92-97, 1998 Free Software Foundation, Inc.
This file is part of GNU CC.
life_analysis fills in certain vectors containing information about
register usage: reg_n_refs, reg_n_deaths, reg_n_sets, reg_live_length,
- reg_n_calls_crosses and reg_basic_block. */
+ reg_n_calls_crosses and reg_basic_block.
+
+ life_analysis sets current_function_sp_is_unchanging if the function
+ doesn't modify the stack pointer. */
\f
-#include <stdio.h>
#include "config.h"
+#include "system.h"
#include "rtl.h"
#include "basic-block.h"
#include "insn-config.h"
#include "flags.h"
#include "output.h"
#include "except.h"
+#include "toplev.h"
+#include "recog.h"
#include "obstack.h"
#define obstack_chunk_alloc xmalloc
#define obstack_chunk_free free
+#define XNMALLOC(TYPE, COUNT) ((TYPE *) xmalloc ((COUNT) * sizeof (TYPE)))
+
/* The contents of the current function definition are allocated
in this obstack, and all are freed at the end of the function.
For top-level functions, this is temporary_obstack.
This is set up by find_basic_blocks and used there and in life_analysis,
and then freed. */
-static int *uid_block_number;
+int *uid_block_number;
/* INSN_VOLATILE (insn) is 1 if the insn refers to anything volatile. */
#define INSN_VOLATILE(INSN) uid_volatile[INSN_UID (INSN)]
static char *uid_volatile;
+/* Nonzero if the second flow pass has completed. */
+int flow2_completed;
+
/* Number of basic blocks in the current function. */
int n_basic_blocks;
int max_regno;
-/* Maximum number of SCRATCH rtx's used in any basic block of this
- function. */
-
-int max_scratch;
-
-/* Number of SCRATCH rtx's in the current block. */
+/* Indexed by n, giving various register information */
-static int num_scratch;
+varray_type reg_n_info;
-/* Indexed by n, giving various register information */
+/* Size of the reg_n_info table. */
-reg_info *reg_n_info;
+unsigned int reg_n_max;
/* Element N is the next insn that uses (hard or pseudo) register number N
within the current basic block; or zero, if there is no such insn.
rtx *basic_block_end;
+/* Element N indicates whether basic block N can be reached through a
+ computed jump. */
+
+char *basic_block_computed_jump_target;
+
/* Element N is a regset describing the registers live
at the start of basic block N.
This info lasts until we finish compiling the function. */
are another pair, etc. */
rtx regs_may_share;
-/* Element N is nonzero if control can drop into basic block N
- from the preceding basic block. Freed after life_analysis. */
+/* Pointer to head of predecessor/successor block list. */
+static int_list_block *flow_int_list_blocks;
+
+/* Element N is the list of successors of basic block N. */
+static int_list_ptr *basic_block_succ;
-static char *basic_block_drops_in;
+/* Element N is the list of predecessors of basic block N. */
+static int_list_ptr *basic_block_pred;
/* Element N is depth within loops of the last insn in basic block number N.
Freed after life_analysis. */
static short *basic_block_loop_depth;
-/* Element N nonzero if basic block N can actually be reached.
- Vector exists only during find_basic_blocks. */
-
-static char *block_live_static;
-
/* Depth within loops of basic block being scanned for lifetime analysis,
plus one. This is the weight attached to references to registers. */
static HARD_REG_SET elim_reg_set;
/* Forward declarations */
-static void find_basic_blocks PROTO((rtx, rtx));
-static void mark_label_ref PROTO((rtx, rtx, int));
-static void life_analysis PROTO((rtx, int));
-void allocate_for_life_analysis PROTO((void));
-void init_regset_vector PROTO((regset *, int, struct obstack *));
-void free_regset_vector PROTO((regset *, int));
+static void find_basic_blocks_1 PROTO((rtx, rtx));
+static void add_edge PROTO((int, int));
+static void add_edge_to_label PROTO((int, rtx));
+static void make_edges PROTO((int));
+static void mark_label_ref PROTO((int, rtx));
+static void delete_unreachable_blocks PROTO((void));
+static int delete_block PROTO((int));
+static void life_analysis_1 PROTO((rtx, int));
static void propagate_block PROTO((regset, rtx, rtx, int,
regset, int));
-static rtx flow_delete_insn PROTO((rtx));
+static int set_noop_p PROTO((rtx));
+static int noop_move_p PROTO((rtx));
+static void record_volatile_insns PROTO((rtx));
+static void mark_regs_live_at_end PROTO((regset));
static int insn_dead_p PROTO((rtx, regset, int));
static int libcall_dead_p PROTO((rtx, regset, rtx, rtx));
static void mark_set_regs PROTO((regset, regset, rtx,
rtx, regset));
static void mark_set_1 PROTO((regset, regset, rtx,
rtx, regset));
+#ifdef AUTO_INC_DEC
static void find_auto_inc PROTO((regset, rtx, rtx));
-static void mark_used_regs PROTO((regset, regset, rtx, int, rtx));
static int try_pre_increment_1 PROTO((rtx));
static int try_pre_increment PROTO((rtx, rtx, HOST_WIDE_INT));
+#endif
+static void mark_used_regs PROTO((regset, regset, rtx, int, rtx));
void dump_flow_info PROTO((FILE *));
+static void add_pred_succ PROTO ((int, int, int_list_ptr *,
+ int_list_ptr *, int *, int *));
+static int_list_ptr alloc_int_list_node PROTO ((int_list_block **));
+static int_list_ptr add_int_list_node PROTO ((int_list_block **,
+ int_list **, int));
+static void init_regset_vector PROTO ((regset *, int,
+ struct obstack *));
+static void count_reg_sets_1 PROTO ((rtx));
+static void count_reg_sets PROTO ((rtx));
+static void count_reg_references PROTO ((rtx));
+static void notice_stack_pointer_modification PROTO ((rtx, rtx));
\f
-/* Find basic blocks of the current function and perform data flow analysis.
+/* Find basic blocks of the current function.
F is the first insn of the function and NREGS the number of register numbers
- in use. */
+ in use.
+ LIVE_REACHABLE_P is non-zero if the caller needs all live blocks to
+ be reachable. This turns on a kludge that causes the control flow
+ information to be inaccurate and not suitable for passes like GCSE. */
void
-flow_analysis (f, nregs, file)
+find_basic_blocks (f, nregs, file)
rtx f;
int nregs;
FILE *file;
register rtx insn;
register int i;
rtx nonlocal_label_list = nonlocal_label_rtx_list ();
+ int in_libcall_block = 0;
-#ifdef ELIMINABLE_REGS
- static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
-#endif
-
- /* Record which registers will be eliminated. We use this in
- mark_used_regs. */
-
- CLEAR_HARD_REG_SET (elim_reg_set);
-
-#ifdef ELIMINABLE_REGS
- for (i = 0; i < sizeof eliminables / sizeof eliminables[0]; i++)
- SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
-#else
- SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
-#endif
+ /* Avoid leaking memory if this is called multiple times per compiled
+ function. */
+ free_bb_memory ();
/* Count the basic blocks. Also find maximum insn uid value used. */
{
+ rtx prev_call = 0;
register RTX_CODE prev_code = JUMP_INSN;
register RTX_CODE code;
-
- max_uid_for_flow = 0;
+ int eh_region = 0;
+ int call_had_abnormal_edge = 0;
for (insn = f, i = 0; insn; insn = NEXT_INSN (insn))
{
+ /* Track when we are inside in LIBCALL block. */
+ if (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
+ && find_reg_note (insn, REG_LIBCALL, NULL_RTX))
+ in_libcall_block = 1;
+
code = GET_CODE (insn);
- if (INSN_UID (insn) > max_uid_for_flow)
- max_uid_for_flow = INSN_UID (insn);
+
+ /* A basic block starts at label, or after something that can jump. */
if (code == CODE_LABEL
|| (GET_RTX_CLASS (code) == 'i'
&& (prev_code == JUMP_INSN
- || (prev_code == CALL_INSN
- && nonlocal_label_list != 0)
+ || (prev_code == CALL_INSN && call_had_abnormal_edge)
|| prev_code == BARRIER)))
- i++;
+ {
+ i++;
+
+ /* If the previous insn was a call that did not create an
+ abnormal edge, we want to add a nop so that the CALL_INSN
+ itself is not at basic_block_end. This allows us to easily
+ distinguish between normal calls and those which create
+ abnormal edges in the flow graph. */
- if (code == CALL_INSN && find_reg_note (insn, REG_RETVAL, NULL_RTX))
+ if (i > 0 && !call_had_abnormal_edge && prev_call != 0)
+ {
+ rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
+ emit_insn_after (nop, prev_call);
+ }
+ }
+ /* We change the code of the CALL_INSN, so that it won't start a
+ new block. */
+ if (code == CALL_INSN && in_libcall_block)
code = INSN;
+ /* Record whether this call created an edge. */
+ if (code == CALL_INSN)
+ {
+ prev_call = insn;
+ call_had_abnormal_edge = (nonlocal_label_list != 0 || eh_region);
+ }
+ else if (code != NOTE && code != BARRIER)
+ prev_call = 0;
+
if (code != NOTE)
prev_code = code;
+ else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)
+ ++eh_region;
+ else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)
+ --eh_region;
+
+ if (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
+ && find_reg_note (insn, REG_RETVAL, NULL_RTX))
+ in_libcall_block = 0;
}
}
+ n_basic_blocks = i;
+
+ max_uid_for_flow = get_max_uid ();
#ifdef AUTO_INC_DEC
- /* Leave space for insns we make in some cases for auto-inc. These cases
- are rare, so we don't need too much space. */
+ /* Leave space for insns life_analysis makes in some cases for auto-inc.
+ These cases are rare, so we don't need too much space. */
max_uid_for_flow += max_uid_for_flow / 10;
#endif
/* Allocate some tables that last till end of compiling this function
and some needed only in find_basic_blocks and life_analysis. */
- n_basic_blocks = i;
- basic_block_head = (rtx *) oballoc (n_basic_blocks * sizeof (rtx));
- basic_block_end = (rtx *) oballoc (n_basic_blocks * sizeof (rtx));
- basic_block_drops_in = (char *) alloca (n_basic_blocks);
- basic_block_loop_depth = (short *) alloca (n_basic_blocks * sizeof (short));
- uid_block_number
- = (int *) alloca ((max_uid_for_flow + 1) * sizeof (int));
- uid_volatile = (char *) alloca (max_uid_for_flow + 1);
+ basic_block_head = XNMALLOC (rtx, n_basic_blocks);
+ basic_block_end = XNMALLOC (rtx, n_basic_blocks);
+ basic_block_succ = XNMALLOC (int_list_ptr, n_basic_blocks);
+ basic_block_pred = XNMALLOC (int_list_ptr, n_basic_blocks);
+ bzero ((char *)basic_block_succ, n_basic_blocks * sizeof (int_list_ptr));
+ bzero ((char *)basic_block_pred, n_basic_blocks * sizeof (int_list_ptr));
+
+ basic_block_computed_jump_target = (char *) oballoc (n_basic_blocks);
+ basic_block_loop_depth = XNMALLOC (short, n_basic_blocks);
+ uid_block_number = XNMALLOC (int, (max_uid_for_flow + 1));
+ uid_volatile = XNMALLOC (char, (max_uid_for_flow + 1));
bzero (uid_volatile, max_uid_for_flow + 1);
- find_basic_blocks (f, nonlocal_label_list);
- life_analysis (f, nregs);
- if (file)
- dump_flow_info (file);
-
- basic_block_drops_in = 0;
- uid_block_number = 0;
- basic_block_loop_depth = 0;
+ find_basic_blocks_1 (f, nonlocal_label_list);
}
-\f
+
+/* For communication between find_basic_blocks_1 and its subroutines. */
+
+/* An array of CODE_LABELs, indexed by UID for the start of the active
+ EH handler for each insn in F. */
+static int *active_eh_region;
+static int *nested_eh_region;
+
+/* Element N nonzero if basic block N can actually be reached. */
+
+static char *block_live_static;
+
+/* List of label_refs to all labels whose addresses are taken
+ and used as data. */
+static rtx label_value_list;
+
+/* a list of non-local labels in the function. */
+static rtx nonlocal_label_list;
+
/* Find all basic blocks of the function whose first insn is F.
Store the correct data in the tables that describe the basic blocks,
set up the chains of references for each CODE_LABEL, and
delete any entire basic blocks that cannot be reached.
- NONLOCAL_LABEL_LIST is the same local variable from flow_analysis. */
+ NONLOCAL_LABELS is a list of non-local labels in the function.
+ Blocks that are otherwise unreachable may be reachable with a non-local
+ goto.
+ LIVE_REACHABLE_P is non-zero if the caller needs all live blocks to
+ be reachable. This turns on a kludge that causes the control flow
+ information to be inaccurate and not suitable for passes like GCSE. */
static void
-find_basic_blocks (f, nonlocal_label_list)
- rtx f, nonlocal_label_list;
+find_basic_blocks_1 (f, nonlocal_labels)
+ rtx f, nonlocal_labels;
{
register rtx insn;
register int i;
register char *block_live = (char *) alloca (n_basic_blocks);
register char *block_marked = (char *) alloca (n_basic_blocks);
- /* List of label_refs to all labels whose addresses are taken
- and used as data. */
- rtx label_value_list;
- int label_value_list_marked_live;
- rtx x, note;
+ rtx note, eh_note;
enum rtx_code prev_code, code;
- int depth, pass;
+ int depth;
+ int in_libcall_block = 0;
+ int call_had_abnormal_edge = 0;
- pass = 1;
- restart:
+ active_eh_region = (int *) alloca ((max_uid_for_flow + 1) * sizeof (int));
+ nested_eh_region = (int *) alloca ((max_label_num () + 1) * sizeof (int));
+ nonlocal_label_list = nonlocal_labels;
label_value_list = 0;
- label_value_list_marked_live = 0;
block_live_static = block_live;
bzero (block_live, n_basic_blocks);
bzero (block_marked, n_basic_blocks);
+ bzero (basic_block_computed_jump_target, n_basic_blocks);
+ bzero ((char *) active_eh_region, (max_uid_for_flow + 1) * sizeof (int));
+ bzero ((char *) nested_eh_region, (max_label_num () + 1) * sizeof (int));
+ current_function_has_computed_jump = 0;
/* Initialize with just block 0 reachable and no blocks marked. */
if (n_basic_blocks > 0)
the block it is in. Also mark as reachable any blocks headed by labels
that must not be deleted. */
- for (insn = f, i = -1, prev_code = JUMP_INSN, depth = 1;
+ for (eh_note = NULL_RTX, insn = f, i = -1, prev_code = JUMP_INSN, depth = 1;
insn; insn = NEXT_INSN (insn))
{
+
+ /* Track when we are inside in LIBCALL block. */
+ if (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
+ && find_reg_note (insn, REG_LIBCALL, NULL_RTX))
+ in_libcall_block = 1;
+
code = GET_CODE (insn);
if (code == NOTE)
{
else if (code == CODE_LABEL
|| (GET_RTX_CLASS (code) == 'i'
&& (prev_code == JUMP_INSN
- || (prev_code == CALL_INSN
- && nonlocal_label_list != 0
- && ! find_reg_note (insn, REG_RETVAL, NULL_RTX))
+ || (prev_code == CALL_INSN && call_had_abnormal_edge)
|| prev_code == BARRIER)))
{
basic_block_head[++i] = insn;
if (code == CODE_LABEL)
{
- LABEL_REFS (insn) = insn;
- /* Any label that cannot be deleted
- is considered to start a reachable block. */
- if (LABEL_PRESERVE_P (insn))
- block_live[i] = 1;
- }
+ LABEL_REFS (insn) = insn;
+ /* Any label that cannot be deleted
+ is considered to start a reachable block. */
+ if (LABEL_PRESERVE_P (insn))
+ block_live[i] = 1;
+ }
}
else if (GET_RTX_CLASS (code) == 'i')
{
/* Make a list of all labels referred to other than by jumps. */
for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
- if (REG_NOTE_KIND (note) == REG_LABEL)
- label_value_list = gen_rtx (EXPR_LIST, VOIDmode, XEXP (note, 0),
- label_value_list);
+ if (REG_NOTE_KIND (note) == REG_LABEL
+ && XEXP (note, 0) != eh_return_stub_label)
+ label_value_list = gen_rtx_EXPR_LIST (VOIDmode, XEXP (note, 0),
+ label_value_list);
}
+ /* Keep a lifo list of the currently active exception notes. */
+ if (GET_CODE (insn) == NOTE)
+ {
+ if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)
+ {
+ if (eh_note)
+ nested_eh_region [NOTE_BLOCK_NUMBER (insn)] =
+ NOTE_BLOCK_NUMBER (XEXP (eh_note, 0));
+ else
+ nested_eh_region [NOTE_BLOCK_NUMBER (insn)] = 0;
+ eh_note = gen_rtx_EXPR_LIST (VOIDmode,
+ insn, eh_note);
+ }
+ else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)
+ eh_note = XEXP (eh_note, 1);
+ }
+ /* If we encounter a CALL_INSN, note which exception handler it
+ might pass control to.
+
+ If doing asynchronous exceptions, record the active EH handler
+ for every insn, since most insns can throw. */
+ else if (eh_note
+ && (asynchronous_exceptions
+ || (GET_CODE (insn) == CALL_INSN
+ && ! in_libcall_block)))
+ active_eh_region[INSN_UID (insn)] =
+ NOTE_BLOCK_NUMBER (XEXP (eh_note, 0));
BLOCK_NUM (insn) = i;
+ /* We change the code of the CALL_INSN, so that it won't start a
+ new block. */
+ if (code == CALL_INSN && in_libcall_block)
+ code = INSN;
+
+ /* Record whether this call created an edge. */
+ if (code == CALL_INSN)
+ call_had_abnormal_edge = (nonlocal_label_list != 0 || eh_note);
+
if (code != NOTE)
prev_code = code;
+
+ if (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
+ && find_reg_note (insn, REG_RETVAL, NULL_RTX))
+ in_libcall_block = 0;
}
- /* During the second pass, `n_basic_blocks' is only an upper bound.
- Only perform the sanity check for the first pass, and on the second
- pass ensure `n_basic_blocks' is set to the correct value. */
- if (pass == 1 && i + 1 != n_basic_blocks)
+ if (i + 1 != n_basic_blocks)
abort ();
- n_basic_blocks = i + 1;
-
- for (x = forced_labels; x; x = XEXP (x, 1))
- if (! LABEL_REF_NONLOCAL_P (x))
- block_live[BLOCK_NUM (XEXP (x, 0))] = 1;
-
- if (asynchronous_exceptions)
- for (x = exception_handler_labels; x; x = XEXP (x, 1))
- block_live[BLOCK_NUM (XEXP (x, 0))] = 1;
-
- /* Record which basic blocks control can drop in to. */
-
- for (i = 0; i < n_basic_blocks; i++)
- {
- for (insn = PREV_INSN (basic_block_head[i]);
- insn && GET_CODE (insn) == NOTE; insn = PREV_INSN (insn))
- ;
-
- basic_block_drops_in[i] = insn && GET_CODE (insn) != BARRIER;
- }
/* Now find which basic blocks can actually be reached
and put all jump insns' LABEL_REFS onto the ref-chains
if (n_basic_blocks > 0)
{
int something_marked = 1;
- int deleted;
-
- /* Find all indirect jump insns and mark them as possibly jumping to all
- the labels whose addresses are explicitly used. This is because,
- when there are computed gotos, we can't tell which labels they jump
- to, of all the possibilities. */
-
- for (insn = f; insn; insn = NEXT_INSN (insn))
- if (computed_jump_p (insn))
- {
- if (label_value_list_marked_live == 0)
- {
- label_value_list_marked_live = 1;
-
- /* This could be made smarter by only considering
- these live, if the computed goto is live. */
-
- /* Don't delete the labels (in this function) that
- are referenced by non-jump instructions. */
-
- for (x = label_value_list; x; x = XEXP (x, 1))
- if (! LABEL_REF_NONLOCAL_P (x))
- block_live[BLOCK_NUM (XEXP (x, 0))] = 1;
- }
-
- for (x = label_value_list; x; x = XEXP (x, 1))
- mark_label_ref (gen_rtx (LABEL_REF, VOIDmode, XEXP (x, 0)),
- insn, 0);
-
- for (x = forced_labels; x; x = XEXP (x, 1))
- mark_label_ref (gen_rtx (LABEL_REF, VOIDmode, XEXP (x, 0)),
- insn, 0);
- }
-
- /* Find all call insns and mark them as possibly jumping
- to all the nonlocal goto handler labels. */
-
- for (insn = f; insn; insn = NEXT_INSN (insn))
- if (GET_CODE (insn) == CALL_INSN
- && ! find_reg_note (insn, REG_RETVAL, NULL_RTX))
- {
- for (x = nonlocal_label_list; x; x = XEXP (x, 1))
- mark_label_ref (gen_rtx (LABEL_REF, VOIDmode, XEXP (x, 0)),
- insn, 0);
-
- if (! asynchronous_exceptions)
- for (x = exception_handler_labels; x; x = XEXP (x, 1))
- mark_label_ref (gen_rtx (LABEL_REF, VOIDmode, XEXP (x, 0)),
- insn, 0);
-
- /* ??? This could be made smarter:
- in some cases it's possible to tell that certain
- calls will not do a nonlocal goto.
-
- For example, if the nested functions that do the
- nonlocal gotos do not have their addresses taken, then
- only calls to those functions or to other nested
- functions that use them could possibly do nonlocal
- gotos. */
- }
-
- /* All blocks associated with labels in label_value_list are
- trivially considered as marked live, if the list is empty.
- We do this to speed up the below code. */
-
- if (label_value_list == 0)
- label_value_list_marked_live = 1;
/* Pass over all blocks, marking each block that is reachable
and has not yet been marked.
for (i = 0; i < n_basic_blocks; i++)
if (block_live[i] && !block_marked[i])
{
+ int_list_ptr p;
+
block_marked[i] = 1;
something_marked = 1;
- if (i + 1 < n_basic_blocks && basic_block_drops_in[i + 1])
- block_live[i + 1] = 1;
- insn = basic_block_end[i];
- if (GET_CODE (insn) == JUMP_INSN)
- mark_label_ref (PATTERN (insn), insn, 0);
-
- if (label_value_list_marked_live == 0)
- /* Now that we know that this block is live, mark as
- live, all the blocks that we might be able to get
- to as live. */
-
- for (insn = basic_block_head[i];
- insn != NEXT_INSN (basic_block_end[i]);
- insn = NEXT_INSN (insn))
- {
- if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
- {
- for (note = REG_NOTES (insn);
- note;
- note = XEXP (note, 1))
- if (REG_NOTE_KIND (note) == REG_LABEL)
- {
- x = XEXP (note, 0);
- block_live[BLOCK_NUM (x)] = 1;
- }
- }
- }
+
+ make_edges (i);
+
+ for (p = basic_block_succ[i]; p; p = p->next)
+ block_live[INT_LIST_VAL (p)] = 1;
}
}
- /* ??? See if we have a "live" basic block that is not reachable.
- This can happen if it is headed by a label that is preserved or
- in one of the label lists, but no call or computed jump is in
- the loop. It's not clear if we can delete the block or not,
- but don't for now. However, we will mess up register status if
- it remains unreachable, so add a fake reachability from the
- previous block. */
+ /* This should never happen. If it does that means we've computed an
+ incorrect flow graph, which can lead to aborts/crashes later in the
+ compiler or incorrect code generation.
+ We used to try and continue here, but that's just asking for trouble
+ later during the compile or at runtime. It's easier to debug the
+ problem here than later! */
for (i = 1; i < n_basic_blocks; i++)
- if (block_live[i] && ! basic_block_drops_in[i]
- && GET_CODE (basic_block_head[i]) == CODE_LABEL
- && LABEL_REFS (basic_block_head[i]) == basic_block_head[i])
- basic_block_drops_in[i] = 1;
-
- /* Now delete the code for any basic blocks that can't be reached.
- They can occur because jump_optimize does not recognize
- unreachable loops as unreachable. */
-
- deleted = 0;
- for (i = 0; i < n_basic_blocks; i++)
- if (!block_live[i])
- {
- deleted++;
-
- /* Delete the insns in a (non-live) block. We physically delete
- every non-note insn except the start and end (so
- basic_block_head/end needn't be updated), we turn the latter
- into NOTE_INSN_DELETED notes.
- We use to "delete" the insns by turning them into notes, but
- we may be deleting lots of insns that subsequent passes would
- otherwise have to process. Secondly, lots of deleted blocks in
- a row can really slow down propagate_block since it will
- otherwise process insn-turned-notes multiple times when it
- looks for loop begin/end notes. */
- if (basic_block_head[i] != basic_block_end[i])
- {
- /* It would be quicker to delete all of these with a single
- unchaining, rather than one at a time, but we need to keep
- the NOTE's. */
- insn = NEXT_INSN (basic_block_head[i]);
- while (insn != basic_block_end[i])
- {
- if (GET_CODE (insn) == BARRIER)
- abort ();
- else if (GET_CODE (insn) != NOTE)
- insn = flow_delete_insn (insn);
- else
- insn = NEXT_INSN (insn);
- }
- }
- insn = basic_block_head[i];
- if (GET_CODE (insn) != NOTE)
- {
- /* Turn the head into a deleted insn note. */
- if (GET_CODE (insn) == BARRIER)
- abort ();
- PUT_CODE (insn, NOTE);
- NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (insn) = 0;
- }
- insn = basic_block_end[i];
- if (GET_CODE (insn) != NOTE)
- {
- /* Turn the tail into a deleted insn note. */
- if (GET_CODE (insn) == BARRIER)
- abort ();
- PUT_CODE (insn, NOTE);
- NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (insn) = 0;
- }
- /* BARRIERs are between basic blocks, not part of one.
- Delete a BARRIER if the preceding jump is deleted.
- We cannot alter a BARRIER into a NOTE
- because it is too short; but we can really delete
- it because it is not part of a basic block. */
- if (NEXT_INSN (insn) != 0
- && GET_CODE (NEXT_INSN (insn)) == BARRIER)
- delete_insn (NEXT_INSN (insn));
-
- /* Each time we delete some basic blocks,
- see if there is a jump around them that is
- being turned into a no-op. If so, delete it. */
-
- if (block_live[i - 1])
- {
- register int j;
- for (j = i + 1; j < n_basic_blocks; j++)
- if (block_live[j])
- {
- rtx label;
- insn = basic_block_end[i - 1];
- if (GET_CODE (insn) == JUMP_INSN
- /* An unconditional jump is the only possibility
- we must check for, since a conditional one
- would make these blocks live. */
- && simplejump_p (insn)
- && (label = XEXP (SET_SRC (PATTERN (insn)), 0), 1)
- && INSN_UID (label) != 0
- && BLOCK_NUM (label) == j)
- {
- PUT_CODE (insn, NOTE);
- NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (insn) = 0;
- if (GET_CODE (NEXT_INSN (insn)) != BARRIER)
- abort ();
- delete_insn (NEXT_INSN (insn));
- }
- break;
- }
- }
- }
+ if (block_live[i] && basic_block_pred[i] == 0)
+ abort ();
- /* There are pathological cases where one function calling hundreds of
- nested inline functions can generate lots and lots of unreachable
- blocks that jump can't delete. Since we don't use sparse matrices
- a lot of memory will be needed to compile such functions.
- Implementing sparse matrices is a fair bit of work and it is not
- clear that they win more than they lose (we don't want to
- unnecessarily slow down compilation of normal code). By making
- another pass for the pathological case, we can greatly speed up
- their compilation without hurting normal code. This works because
- all the insns in the unreachable blocks have either been deleted or
- turned into notes.
- Note that we're talking about reducing memory usage by 10's of
- megabytes and reducing compilation time by several minutes. */
- /* ??? The choice of when to make another pass is a bit arbitrary,
- and was derived from empirical data. */
- if (pass == 1
- && deleted > 200)
- {
- pass++;
- n_basic_blocks -= deleted;
- /* `n_basic_blocks' may not be correct at this point: two previously
- separate blocks may now be merged. That's ok though as we
- recalculate it during the second pass. It certainly can't be
- any larger than the current value. */
- goto restart;
- }
+ if (! reload_completed)
+ delete_unreachable_blocks ();
+ }
+}
+
+/* Record INSN's block number as BB. */
+
+void
+set_block_num (insn, bb)
+ rtx insn;
+ int bb;
+{
+ if (INSN_UID (insn) >= max_uid_for_flow)
+ {
+ /* Add one-eighth the size so we don't keep calling xrealloc. */
+ max_uid_for_flow = INSN_UID (insn) + (INSN_UID (insn) + 7) / 8;
+ uid_block_number = (int *)
+ xrealloc (uid_block_number, (max_uid_for_flow + 1) * sizeof (int));
}
+ BLOCK_NUM (insn) = bb;
}
\f
/* Subroutines of find_basic_blocks. */
-/* Check expression X for label references;
- if one is found, add INSN to the label's chain of references.
+void
+free_bb_memory ()
+{
+ free_int_list (&flow_int_list_blocks);
+}
+
+/* Make an edge in the cfg from block PRED to block SUCC. */
+static void
+add_edge (pred, succ)
+ int pred, succ;
+{
+ add_int_list_node (&flow_int_list_blocks, basic_block_pred + succ, pred);
+ add_int_list_node (&flow_int_list_blocks, basic_block_succ + pred, succ);
+}
+
+/* Make an edge in the cfg from block PRED to the block starting with
+ label LABEL. */
+static void
+add_edge_to_label (pred, label)
+ int pred;
+ rtx label;
+{
+ /* If the label was never emitted, this insn is junk,
+ but avoid a crash trying to refer to BLOCK_NUM (label).
+ This can happen as a result of a syntax error
+ and a diagnostic has already been printed. */
+ if (INSN_UID (label) == 0)
+ return;
+
+ add_edge (pred, BLOCK_NUM (label));
+}
- CHECKDUP means check for and avoid creating duplicate references
- from the same insn. Such duplicates do no serious harm but
- can slow life analysis. CHECKDUP is set only when duplicates
- are likely. */
+/* Check expression X for label references. If one is found, add an edge
+ from basic block PRED to the block beginning with the label. */
static void
-mark_label_ref (x, insn, checkdup)
- rtx x, insn;
- int checkdup;
+mark_label_ref (pred, x)
+ int pred;
+ rtx x;
{
register RTX_CODE code;
register int i;
register char *fmt;
- /* We can be called with NULL when scanning label_value_list. */
- if (x == 0)
- return;
-
code = GET_CODE (x);
if (code == LABEL_REF)
{
- register rtx label = XEXP (x, 0);
- register rtx y;
- if (GET_CODE (label) != CODE_LABEL)
- abort ();
- /* If the label was never emitted, this insn is junk,
- but avoid a crash trying to refer to BLOCK_NUM (label).
- This can happen as a result of a syntax error
- and a diagnostic has already been printed. */
- if (INSN_UID (label) == 0)
- return;
- CONTAINING_INSN (x) = insn;
- /* if CHECKDUP is set, check for duplicate ref from same insn
- and don't insert. */
- if (checkdup)
- for (y = LABEL_REFS (label); y != label; y = LABEL_NEXTREF (y))
- if (CONTAINING_INSN (y) == insn)
- return;
- LABEL_NEXTREF (x) = LABEL_REFS (label);
- LABEL_REFS (label) = x;
- block_live_static[BLOCK_NUM (label)] = 1;
+ add_edge_to_label (pred, XEXP (x, 0));
return;
}
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
{
if (fmt[i] == 'e')
- mark_label_ref (XEXP (x, i), insn, 0);
+ mark_label_ref (pred, XEXP (x, i));
if (fmt[i] == 'E')
{
register int j;
for (j = 0; j < XVECLEN (x, i); j++)
- mark_label_ref (XVECEXP (x, i, j), insn, 1);
+ mark_label_ref (pred, XVECEXP (x, i, j));
}
}
}
-/* Delete INSN by patching it out.
- Return the next insn. */
-
-static rtx
-flow_delete_insn (insn)
- rtx insn;
-{
- /* ??? For the moment we assume we don't have to watch for NULLs here
- since the start/end of basic blocks aren't deleted like this. */
- NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
- PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
- return NEXT_INSN (insn);
-}
-\f
-/* Determine which registers are live at the start of each
- basic block of the function whose first insn is F.
- NREGS is the number of registers used in F.
- We allocate the vector basic_block_live_at_start
- and the regsets that it points to, and fill them with the data.
- regset_size and regset_bytes are also set here. */
-
+/* For basic block I, make edges and mark live all blocks which are reachable
+ from it. */
static void
-life_analysis (f, nregs)
- rtx f;
- int nregs;
+make_edges (i)
+ int i;
{
- int first_pass;
- int changed;
- /* For each basic block, a bitmask of regs
- live on exit from the block. */
- regset *basic_block_live_at_end;
- /* For each basic block, a bitmask of regs
- live on entry to a successor-block of this block.
- If this does not match basic_block_live_at_end,
- that must be updated, and the block must be rescanned. */
- regset *basic_block_new_live_at_end;
- /* For each basic block, a bitmask of regs
- whose liveness at the end of the basic block
- can make a difference in which regs are live on entry to the block.
- These are the regs that are set within the basic block,
- possibly excluding those that are used after they are set. */
- regset *basic_block_significant;
- register int i;
- rtx insn;
-
- struct obstack flow_obstack;
-
- gcc_obstack_init (&flow_obstack);
+ rtx insn, x;
- max_regno = nregs;
-
- bzero (regs_ever_live, sizeof regs_ever_live);
-
- /* Allocate and zero out many data structures
- that will record the data from lifetime analysis. */
-
- allocate_for_life_analysis ();
-
- reg_next_use = (rtx *) alloca (nregs * sizeof (rtx));
- bzero ((char *) reg_next_use, nregs * sizeof (rtx));
-
- /* Set up several regset-vectors used internally within this function.
- Their meanings are documented above, with their declarations. */
-
- basic_block_live_at_end
- = (regset *) alloca (n_basic_blocks * sizeof (regset));
-
- /* Don't use alloca since that leads to a crash rather than an error message
- if there isn't enough space.
- Don't use oballoc since we may need to allocate other things during
- this function on the temporary obstack. */
- init_regset_vector (basic_block_live_at_end, n_basic_blocks, &flow_obstack);
-
- basic_block_new_live_at_end
- = (regset *) alloca (n_basic_blocks * sizeof (regset));
- init_regset_vector (basic_block_new_live_at_end, n_basic_blocks,
- &flow_obstack);
+ /* See if control drops into the next block. */
+ if (i + 1 < n_basic_blocks)
+ {
+ for (insn = PREV_INSN (basic_block_head[i + 1]);
+ insn && GET_CODE (insn) == NOTE; insn = PREV_INSN (insn))
+ ;
- basic_block_significant
- = (regset *) alloca (n_basic_blocks * sizeof (regset));
- init_regset_vector (basic_block_significant, n_basic_blocks, &flow_obstack);
+ if (insn && GET_CODE (insn) != BARRIER)
+ add_edge (i, i + 1);
+ }
- /* Record which insns refer to any volatile memory
- or for any reason can't be deleted just because they are dead stores.
- Also, delete any insns that copy a register to itself. */
+ insn = basic_block_end[i];
+ if (GET_CODE (insn) == JUMP_INSN)
+ mark_label_ref (i, PATTERN (insn));
- for (insn = f; insn; insn = NEXT_INSN (insn))
+ /* If we have any forced labels, mark them as potentially reachable from
+ this block. */
+ for (x = forced_labels; x; x = XEXP (x, 1))
+ if (! LABEL_REF_NONLOCAL_P (x))
+ add_edge_to_label (i, XEXP (x, 0));
+
+ /* Now scan the insns for this block, we may need to make edges for some of
+ them to various non-obvious locations (exception handlers, nonlocal
+ labels, etc). */
+ for (insn = basic_block_head[i];
+ insn != NEXT_INSN (basic_block_end[i]);
+ insn = NEXT_INSN (insn))
{
- enum rtx_code code1 = GET_CODE (insn);
- if (code1 == CALL_INSN)
- INSN_VOLATILE (insn) = 1;
- else if (code1 == INSN || code1 == JUMP_INSN)
+ if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
{
- /* Delete (in effect) any obvious no-op moves. */
- if (GET_CODE (PATTERN (insn)) == SET
- && GET_CODE (SET_DEST (PATTERN (insn))) == REG
- && GET_CODE (SET_SRC (PATTERN (insn))) == REG
- && (REGNO (SET_DEST (PATTERN (insn)))
- == REGNO (SET_SRC (PATTERN (insn))))
- /* Insns carrying these notes are useful later on. */
- && ! find_reg_note (insn, REG_EQUAL, NULL_RTX))
+ rtx note;
+ /* References to labels in non-jumping insns have REG_LABEL notes
+ attached to them.
+
+ This can happen for computed gotos; we don't care about them
+ here since the values are also on the label_value_list and will
+ be marked live if we find a live computed goto.
+
+ This can also happen when we take the address of a label to pass
+ as an argument to __throw. Note throw only uses the value to
+ determine what handler should be called -- ie the label is not
+ used as a jump target, it just marks regions in the code.
+
+ In theory we should be able to ignore the REG_LABEL notes, but
+ we have to make sure that the label and associated insns aren't
+ marked dead, so we make the block in question live and create an
+ edge from this insn to the label. This is not strictly correct,
+ but it is close enough for now.
+
+ See below for code that handles the eh_stub label specially. */
+ for (note = REG_NOTES (insn);
+ note;
+ note = XEXP (note, 1))
{
- PUT_CODE (insn, NOTE);
- NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (insn) = 0;
+ if (REG_NOTE_KIND (note) == REG_LABEL
+ && XEXP (note, 0) != eh_return_stub_label)
+ add_edge_to_label (i, XEXP (note, 0));
}
- /* Delete (in effect) any obvious no-op moves. */
- else if (GET_CODE (PATTERN (insn)) == SET
- && GET_CODE (SET_DEST (PATTERN (insn))) == SUBREG
- && GET_CODE (SUBREG_REG (SET_DEST (PATTERN (insn)))) == REG
- && GET_CODE (SET_SRC (PATTERN (insn))) == SUBREG
- && GET_CODE (SUBREG_REG (SET_SRC (PATTERN (insn)))) == REG
- && (REGNO (SUBREG_REG (SET_DEST (PATTERN (insn))))
- == REGNO (SUBREG_REG (SET_SRC (PATTERN (insn)))))
- && SUBREG_WORD (SET_DEST (PATTERN (insn))) ==
- SUBREG_WORD (SET_SRC (PATTERN (insn)))
- /* Insns carrying these notes are useful later on. */
- && ! find_reg_note (insn, REG_EQUAL, NULL_RTX))
+
+ /* If this is a computed jump, then mark it as reaching everything
+ on the label_value_list and forced_labels list. */
+ if (computed_jump_p (insn))
{
- PUT_CODE (insn, NOTE);
- NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (insn) = 0;
+ current_function_has_computed_jump = 1;
+ for (x = label_value_list; x; x = XEXP (x, 1))
+ {
+ int b = BLOCK_NUM (XEXP (x, 0));
+ basic_block_computed_jump_target[b] = 1;
+ add_edge (i, b);
+ }
+
+ for (x = forced_labels; x; x = XEXP (x, 1))
+ {
+ int b = BLOCK_NUM (XEXP (x, 0));
+ basic_block_computed_jump_target[b] = 1;
+ add_edge (i, b);
+ }
}
- else if (GET_CODE (PATTERN (insn)) == PARALLEL)
+
+ /* If this is a CALL_INSN, then mark it as reaching the active EH
+ handler for this CALL_INSN. If we're handling asynchronous
+ exceptions mark every insn as reaching the active EH handler.
+
+ Also mark the CALL_INSN as reaching any nonlocal goto sites. */
+ else if (asynchronous_exceptions
+ || (GET_CODE (insn) == CALL_INSN
+ && ! find_reg_note (insn, REG_RETVAL, NULL_RTX)))
{
- /* If nothing but SETs of registers to themselves,
- this insn can also be deleted. */
- for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++)
+ if (active_eh_region[INSN_UID (insn)])
{
- rtx tem = XVECEXP (PATTERN (insn), 0, i);
-
- if (GET_CODE (tem) == USE
- || GET_CODE (tem) == CLOBBER)
- continue;
-
- if (GET_CODE (tem) != SET
- || GET_CODE (SET_DEST (tem)) != REG
- || GET_CODE (SET_SRC (tem)) != REG
- || REGNO (SET_DEST (tem)) != REGNO (SET_SRC (tem)))
- break;
+ int region;
+ handler_info *ptr;
+ region = active_eh_region[INSN_UID (insn)];
+ for ( ; region; region = nested_eh_region[region])
+ {
+ ptr = get_first_handler (region);
+ for ( ; ptr ; ptr = ptr->next)
+ add_edge_to_label (i, ptr->handler_label);
+ }
}
-
- if (i == XVECLEN (PATTERN (insn), 0)
- /* Insns carrying these notes are useful later on. */
- && ! find_reg_note (insn, REG_EQUAL, NULL_RTX))
+ if (! asynchronous_exceptions)
{
- PUT_CODE (insn, NOTE);
- NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (insn) = 0;
+ for (x = nonlocal_label_list; x; x = XEXP (x, 1))
+ add_edge_to_label (i, XEXP (x, 0));
}
- else
- INSN_VOLATILE (insn) = volatile_refs_p (PATTERN (insn));
+ /* ??? This could be made smarter: in some cases it's possible
+ to tell that certain calls will not do a nonlocal goto.
+
+ For example, if the nested functions that do the nonlocal
+ gotos do not have their addresses taken, then only calls to
+ those functions or to other nested functions that use them
+ could possibly do nonlocal gotos. */
}
- else if (GET_CODE (PATTERN (insn)) != USE)
- INSN_VOLATILE (insn) = volatile_refs_p (PATTERN (insn));
- /* A SET that makes space on the stack cannot be dead.
- (Such SETs occur only for allocating variable-size data,
- so they will always have a PLUS or MINUS according to the
- direction of stack growth.)
- Even if this function never uses this stack pointer value,
- signal handlers do! */
- else if (code1 == INSN && GET_CODE (PATTERN (insn)) == SET
- && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
-#ifdef STACK_GROWS_DOWNWARD
- && GET_CODE (SET_SRC (PATTERN (insn))) == MINUS
-#else
- && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
-#endif
- && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx)
- INSN_VOLATILE (insn) = 1;
}
}
+ /* We know something about the structure of the function __throw in
+ libgcc2.c. It is the only function that ever contains eh_stub labels.
+ It modifies its return address so that the last block returns to one of
+ the eh_stub labels within it. So we have to make additional edges in
+ the flow graph. */
+ if (i + 1 == n_basic_blocks && eh_return_stub_label != 0)
+ add_edge_to_label (i, eh_return_stub_label);
+}
- if (n_basic_blocks > 0)
-#ifdef EXIT_IGNORE_STACK
- if (! EXIT_IGNORE_STACK
- || (! FRAME_POINTER_REQUIRED && flag_omit_frame_pointer))
-#endif
+/* Now delete the code for any basic blocks that can't be reached.
+ They can occur because jump_optimize does not recognize unreachable loops
+ as unreachable. */
+static void
+delete_unreachable_blocks ()
+{
+ int deleted_handler = 0;
+ int deleted = 0;
+ int i, j;
+ rtx insn;
+ int *block_num_map = XNMALLOC (int, n_basic_blocks);
+
+ for (i = n_basic_blocks - 1; i >= 0; i--)
+ if (! block_live_static[i])
+ deleted_handler |= delete_block (i);
+
+ for (i = 0; i < n_basic_blocks; i++)
+ if (block_live_static[i])
+ block_num_map[i] = i - deleted;
+ else
{
- /* If exiting needs the right stack value,
- consider the stack pointer live at the end of the function. */
- SET_REGNO_REG_SET (basic_block_live_at_end[n_basic_blocks - 1],
- STACK_POINTER_REGNUM);
- SET_REGNO_REG_SET (basic_block_new_live_at_end[n_basic_blocks - 1],
- STACK_POINTER_REGNUM);
+ deleted++;
+ block_num_map[i] = -1;
}
- /* Mark the frame pointer is needed at the end of the function. If
- we end up eliminating it, it will be removed from the live list
- of each basic block by reload. */
-
- if (n_basic_blocks > 0)
+ /* Eliminate all traces of the deleted blocks by renumbering the remaining
+ ones. */
+ for (i = j = 0; i < n_basic_blocks; i++)
{
- SET_REGNO_REG_SET (basic_block_live_at_end[n_basic_blocks - 1],
- FRAME_POINTER_REGNUM);
- SET_REGNO_REG_SET (basic_block_new_live_at_end[n_basic_blocks - 1],
- FRAME_POINTER_REGNUM);
-#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
- /* If they are different, also mark the hard frame pointer as live */
- SET_REGNO_REG_SET (basic_block_live_at_end[n_basic_blocks - 1],
- HARD_FRAME_POINTER_REGNUM);
- SET_REGNO_REG_SET (basic_block_new_live_at_end[n_basic_blocks - 1],
- HARD_FRAME_POINTER_REGNUM);
-#endif
- }
+ int_list_ptr p;
- /* Mark all global registers and all registers used by the epilogue
- as being live at the end of the function since they may be
- referenced by our caller. */
+ if (block_num_map[i] == -1)
+ continue;
- if (n_basic_blocks > 0)
- for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
- if (global_regs[i]
-#ifdef EPILOGUE_USES
- || EPILOGUE_USES (i)
-#endif
- )
+ for (p = basic_block_pred[i]; p; p = p->next)
+ INT_LIST_VAL (p) = block_num_map[INT_LIST_VAL (p)];
+ for (p = basic_block_succ[i]; p; p = p->next)
+ INT_LIST_VAL (p) = block_num_map[INT_LIST_VAL (p)];
+
+ if (i != j)
{
- SET_REGNO_REG_SET (basic_block_live_at_end[n_basic_blocks - 1], i);
- SET_REGNO_REG_SET (basic_block_new_live_at_end[n_basic_blocks - 1], i);
+ rtx tmp = basic_block_head[i];
+ for (;;)
+ {
+ BLOCK_NUM (tmp) = j;
+ if (tmp == basic_block_end[i])
+ break;
+ tmp = NEXT_INSN (tmp);
+ }
+ basic_block_head[j] = basic_block_head[i];
+ basic_block_end[j] = basic_block_end[i];
+ basic_block_pred[j] = basic_block_pred[i];
+ basic_block_succ[j] = basic_block_succ[i];
+ basic_block_loop_depth[j] = basic_block_loop_depth[i];
+ basic_block_computed_jump_target[j]
+ = basic_block_computed_jump_target[i];
}
+ j++;
+ }
+ n_basic_blocks -= deleted;
+ free (block_num_map);
- /* Propagate life info through the basic blocks
- around the graph of basic blocks.
-
- This is a relaxation process: each time a new register
- is live at the end of the basic block, we must scan the block
- to determine which registers are, as a consequence, live at the beginning
- of that block. These registers must then be marked live at the ends
- of all the blocks that can transfer control to that block.
- The process continues until it reaches a fixed point. */
-
- first_pass = 1;
- changed = 1;
- while (changed)
- {
- changed = 0;
- for (i = n_basic_blocks - 1; i >= 0; i--)
+ /* If we deleted an exception handler, we may have EH region
+ begin/end blocks to remove as well. */
+ if (deleted_handler)
+ for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
+ if (GET_CODE (insn) == NOTE)
{
- int consider = first_pass;
- int must_rescan = first_pass;
- register int j;
-
- if (!first_pass)
+ if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG ||
+ NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)
{
- /* Set CONSIDER if this block needs thinking about at all
- (that is, if the regs live now at the end of it
- are not the same as were live at the end of it when
- we last thought about it).
- Set must_rescan if it needs to be thought about
- instruction by instruction (that is, if any additional
- reg that is live at the end now but was not live there before
- is one of the significant regs of this basic block). */
-
- EXECUTE_IF_AND_COMPL_IN_REG_SET
- (basic_block_new_live_at_end[i],
- basic_block_live_at_end[i], 0, j,
- {
- consider = 1;
- if (REGNO_REG_SET_P (basic_block_significant[i], j))
- {
- must_rescan = 1;
- goto done;
- }
- });
- done:
- if (! consider)
- continue;
+ int num = CODE_LABEL_NUMBER (insn);
+ /* A NULL handler indicates a region is no longer needed */
+ if (get_first_handler (num) == NULL)
+ {
+ NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
+ NOTE_SOURCE_FILE (insn) = 0;
+ }
}
+ }
+}
- /* The live_at_start of this block may be changing,
- so another pass will be required after this one. */
- changed = 1;
+/* Delete the insns in a (non-live) block. We physically delete every
+ non-note insn except the start and end (so basic_block_head/end needn't
+ be updated), we turn the latter into NOTE_INSN_DELETED notes.
- if (! must_rescan)
- {
- /* No complete rescan needed;
- just record those variables newly known live at end
- as live at start as well. */
- IOR_AND_COMPL_REG_SET (basic_block_live_at_start[i],
- basic_block_new_live_at_end[i],
- basic_block_live_at_end[i]);
+ We use to "delete" the insns by turning them into notes, but we may be
+ deleting lots of insns that subsequent passes would otherwise have to
+ process. Secondly, lots of deleted blocks in a row can really slow down
+ propagate_block since it will otherwise process insn-turned-notes multiple
+ times when it looks for loop begin/end notes.
- IOR_AND_COMPL_REG_SET (basic_block_live_at_end[i],
- basic_block_new_live_at_end[i],
- basic_block_live_at_end[i]);
+ Return nonzero if we deleted an exception handler. */
+static int
+delete_block (i)
+ int i;
+{
+ int deleted_handler = 0;
+ rtx insn;
+ rtx kept_head = 0;
+ rtx kept_tail = 0;
+
+ /* If the head of this block is a CODE_LABEL, then it might
+ be the label for an exception handler which can't be
+ reached.
+
+ We need to remove the label from the exception_handler_label
+ list and remove the associated NOTE_EH_REGION_BEG and
+ NOTE_EH_REGION_END notes. */
+ insn = basic_block_head[i];
+ if (GET_CODE (insn) == CODE_LABEL)
+ {
+ rtx x, *prev = &exception_handler_labels;
+
+ for (x = exception_handler_labels; x; x = XEXP (x, 1))
+ {
+ if (XEXP (x, 0) == insn)
+ {
+ /* Found a match, splice this label out of the
+ EH label list. */
+ *prev = XEXP (x, 1);
+ XEXP (x, 1) = NULL_RTX;
+ XEXP (x, 0) = NULL_RTX;
+
+ /* Remove the handler from all regions */
+ remove_handler (insn);
+ deleted_handler = 1;
+ break;
}
+ prev = &XEXP (x, 1);
+ }
+ }
+
+ /* Walk the insns of the block, building a chain of NOTEs that need to be
+ kept. */
+ insn = basic_block_head[i];
+ for (;;)
+ {
+ if (GET_CODE (insn) == BARRIER)
+ abort ();
+ else if (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) != NOTE_INSN_DELETED)
+ {
+ if (kept_head == 0)
+ kept_head = kept_tail = insn;
else
{
- /* Update the basic_block_live_at_start
- by propagation backwards through the block. */
- COPY_REG_SET (basic_block_live_at_end[i],
- basic_block_new_live_at_end[i]);
- COPY_REG_SET (basic_block_live_at_start[i],
- basic_block_live_at_end[i]);
- propagate_block (basic_block_live_at_start[i],
- basic_block_head[i], basic_block_end[i], 0,
- first_pass ? basic_block_significant[i]
- : (regset) 0,
- i);
+ NEXT_INSN (kept_tail) = insn;
+ PREV_INSN (insn) = kept_tail;
+ kept_tail = insn;
}
+ }
+ if (insn == basic_block_end[i])
+ break;
+ insn = NEXT_INSN (insn);
+ }
+ insn = NEXT_INSN (insn);
+
+ /* BARRIERs are between basic blocks, not part of one.
+ Delete a BARRIER if the preceding jump is deleted.
+ We cannot alter a BARRIER into a NOTE
+ because it is too short; but we can really delete
+ it because it is not part of a basic block. */
+ if (insn != 0 && GET_CODE (insn) == BARRIER)
+ insn = NEXT_INSN (insn);
+
+ /* Now unchain all of the block, and put the chain of kept notes in its
+ place. */
+ if (kept_head == 0)
+ {
+ NEXT_INSN (PREV_INSN (basic_block_head[i])) = insn;
+ if (insn != 0)
+ PREV_INSN (insn) = PREV_INSN (basic_block_head[i]);
+ }
+ else
+ {
+ NEXT_INSN (PREV_INSN (basic_block_head[i])) = kept_head;
+ if (insn != 0)
+ PREV_INSN (insn) = kept_tail;
- {
- register rtx jump, head;
+ PREV_INSN (kept_head) = PREV_INSN (basic_block_head[i]);
+ NEXT_INSN (kept_tail) = insn;
+ }
- /* Update the basic_block_new_live_at_end's of the block
- that falls through into this one (if any). */
- head = basic_block_head[i];
- if (basic_block_drops_in[i])
- IOR_REG_SET (basic_block_new_live_at_end[i-1],
- basic_block_live_at_start[i]);
+ /* Each time we delete some basic blocks,
+ see if there is a jump around them that is
+ being turned into a no-op. If so, delete it. */
- /* Update the basic_block_new_live_at_end's of
- all the blocks that jump to this one. */
- if (GET_CODE (head) == CODE_LABEL)
- for (jump = LABEL_REFS (head);
- jump != head;
- jump = LABEL_NEXTREF (jump))
- {
- register int from_block = BLOCK_NUM (CONTAINING_INSN (jump));
- IOR_REG_SET (basic_block_new_live_at_end[from_block],
- basic_block_live_at_start[i]);
- }
+ if (block_live_static[i - 1])
+ {
+ register int j;
+ for (j = i + 1; j < n_basic_blocks; j++)
+ if (block_live_static[j])
+ {
+ rtx label;
+ insn = basic_block_end[i - 1];
+ if (GET_CODE (insn) == JUMP_INSN
+ /* An unconditional jump is the only possibility
+ we must check for, since a conditional one
+ would make these blocks live. */
+ && simplejump_p (insn)
+ && (label = XEXP (SET_SRC (PATTERN (insn)), 0), 1)
+ && INSN_UID (label) != 0
+ && BLOCK_NUM (label) == j)
+ {
+ PUT_CODE (insn, NOTE);
+ NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
+ NOTE_SOURCE_FILE (insn) = 0;
+ if (GET_CODE (NEXT_INSN (insn)) != BARRIER)
+ abort ();
+ delete_insn (NEXT_INSN (insn));
+ }
+ break;
}
-#ifdef USE_C_ALLOCA
- alloca (0);
-#endif
- }
- first_pass = 0;
}
- /* The only pseudos that are live at the beginning of the function are
- those that were not set anywhere in the function. local-alloc doesn't
- know how to handle these correctly, so mark them as not local to any
- one basic block. */
-
- if (n_basic_blocks > 0)
- EXECUTE_IF_SET_IN_REG_SET (basic_block_live_at_start[0],
- FIRST_PSEUDO_REGISTER, i,
- {
- REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL;
- });
+ return deleted_handler;
+}
+\f
+/* Perform data flow analysis.
+ F is the first insn of the function and NREGS the number of register numbers
+ in use. */
- /* Now the life information is accurate.
- Make one more pass over each basic block
- to delete dead stores, create autoincrement addressing
- and record how many times each register is used, is set, or dies.
+void
+life_analysis (f, nregs, file)
+ rtx f;
+ int nregs;
+ FILE *file;
+{
+#ifdef ELIMINABLE_REGS
+ register size_t i;
+ static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
+#endif
- To save time, we operate directly in basic_block_live_at_end[i],
- thus destroying it (in fact, converting it into a copy of
- basic_block_live_at_start[i]). This is ok now because
- basic_block_live_at_end[i] is no longer used past this point. */
+ /* Record which registers will be eliminated. We use this in
+ mark_used_regs. */
- max_scratch = 0;
+ CLEAR_HARD_REG_SET (elim_reg_set);
- for (i = 0; i < n_basic_blocks; i++)
- {
- propagate_block (basic_block_live_at_end[i],
- basic_block_head[i], basic_block_end[i], 1,
- (regset) 0, i);
-#ifdef USE_C_ALLOCA
- alloca (0);
+#ifdef ELIMINABLE_REGS
+ for (i = 0; i < sizeof eliminables / sizeof eliminables[0]; i++)
+ SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
+#else
+ SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
#endif
- }
-#if 0
- /* Something live during a setjmp should not be put in a register
- on certain machines which restore regs from stack frames
- rather than from the jmpbuf.
- But we don't need to do this for the user's variables, since
- ANSI says only volatile variables need this. */
-#ifdef LONGJMP_RESTORE_FROM_STACK
- EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
- FIRST_PSEUDO_REGISTER, i,
- {
- if (regno_reg_rtx[i] != 0
- && ! REG_USERVAR_P (regno_reg_rtx[i]))
- {
- REG_LIVE_LENGTH (i) = -1;
- REG_BASIC_BLOCK (i) = -1;
- }
- });
-#endif
-#endif
+ life_analysis_1 (f, nregs);
+ if (file)
+ dump_flow_info (file);
- /* We have a problem with any pseudoreg that
- lives across the setjmp. ANSI says that if a
- user variable does not change in value
- between the setjmp and the longjmp, then the longjmp preserves it.
- This includes longjmp from a place where the pseudo appears dead.
- (In principle, the value still exists if it is in scope.)
- If the pseudo goes in a hard reg, some other value may occupy
- that hard reg where this pseudo is dead, thus clobbering the pseudo.
- Conclusion: such a pseudo must not go in a hard reg. */
- EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
- FIRST_PSEUDO_REGISTER, i,
- {
- if (regno_reg_rtx[i] != 0)
- {
- REG_LIVE_LENGTH (i) = -1;
- REG_BASIC_BLOCK (i) = -1;
- }
- });
+ free_basic_block_vars (1);
+}
+/* Free the variables allocated by find_basic_blocks.
- free_regset_vector (basic_block_live_at_end, n_basic_blocks);
- free_regset_vector (basic_block_new_live_at_end, n_basic_blocks);
- free_regset_vector (basic_block_significant, n_basic_blocks);
- basic_block_live_at_end = (regset *)0;
- basic_block_new_live_at_end = (regset *)0;
- basic_block_significant = (regset *)0;
+ KEEP_HEAD_END_P is non-zero if basic_block_head and basic_block_end
+ are not to be freed. */
- obstack_free (&flow_obstack, NULL_PTR);
-}
-\f
-/* Subroutines of life analysis. */
+void
+free_basic_block_vars (keep_head_end_p)
+ int keep_head_end_p;
+{
+ if (basic_block_loop_depth)
+ {
+ free (basic_block_loop_depth);
+ basic_block_loop_depth = 0;
+ }
+ if (uid_block_number)
+ {
+ free (uid_block_number);
+ uid_block_number = 0;
+ }
+ if (uid_volatile)
+ {
+ free (uid_volatile);
+ uid_volatile = 0;
+ }
-/* Allocate the permanent data structures that represent the results
- of life analysis. Not static since used also for stupid life analysis. */
+ if (! keep_head_end_p && basic_block_head)
+ {
+ free (basic_block_head);
+ basic_block_head = 0;
+ free (basic_block_end);
+ basic_block_end = 0;
+ }
+}
-void
-allocate_for_life_analysis ()
+/* Return nonzero if the destination of SET equals the source. */
+static int
+set_noop_p (set)
+ rtx set;
{
- register int i;
+ rtx src = SET_SRC (set);
+ rtx dst = SET_DEST (set);
+ if (GET_CODE (src) == REG && GET_CODE (dst) == REG
+ && REGNO (src) == REGNO (dst))
+ return 1;
+ if (GET_CODE (src) != SUBREG || GET_CODE (dst) != SUBREG
+ || SUBREG_WORD (src) != SUBREG_WORD (dst))
+ return 0;
+ src = SUBREG_REG (src);
+ dst = SUBREG_REG (dst);
+ if (GET_CODE (src) == REG && GET_CODE (dst) == REG
+ && REGNO (src) == REGNO (dst))
+ return 1;
+ return 0;
+}
- /* Recalculate the register space, in case it has grown. Old style
- vector oriented regsets would set regset_{size,bytes} here also. */
- allocate_reg_info (max_regno, FALSE, FALSE);
+/* Return nonzero if an insn consists only of SETs, each of which only sets a
+ value to itself. */
+static int
+noop_move_p (insn)
+ rtx insn;
+{
+ rtx pat = PATTERN (insn);
- /* Because both reg_scan and flow_analysis want to set up the REG_N_SETS
- information, explicitly reset it here. The allocation should have
- already happened on the previous reg_scan pass. Make sure in case
- some more registers were allocated. */
- for (i = 0; i < max_regno; i++)
- REG_N_SETS (i) = 0;
+ /* Insns carrying these notes are useful later on. */
+ if (find_reg_note (insn, REG_EQUAL, NULL_RTX))
+ return 0;
- basic_block_live_at_start
- = (regset *) oballoc (n_basic_blocks * sizeof (regset));
- init_regset_vector (basic_block_live_at_start, n_basic_blocks,
- function_obstack);
+ if (GET_CODE (pat) == SET && set_noop_p (pat))
+ return 1;
- regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (function_obstack);
- CLEAR_REG_SET (regs_live_at_setjmp);
-}
+ if (GET_CODE (pat) == PARALLEL)
+ {
+ int i;
+ /* If nothing but SETs of registers to themselves,
+ this insn can also be deleted. */
+ for (i = 0; i < XVECLEN (pat, 0); i++)
+ {
+ rtx tem = XVECEXP (pat, 0, i);
-/* Make each element of VECTOR point at a regset. The vector has
- NELTS elements, and space is allocated from the ALLOC_OBSTACK
- obstack. */
+ if (GET_CODE (tem) == USE
+ || GET_CODE (tem) == CLOBBER)
+ continue;
-void
-init_regset_vector (vector, nelts, alloc_obstack)
- regset *vector;
- int nelts;
- struct obstack *alloc_obstack;
-{
- register int i;
+ if (GET_CODE (tem) != SET || ! set_noop_p (tem))
+ return 0;
+ }
- for (i = 0; i < nelts; i++)
- {
- vector[i] = OBSTACK_ALLOC_REG_SET (alloc_obstack);
- CLEAR_REG_SET (vector[i]);
+ return 1;
}
+ return 0;
}
-/* Release any additional space allocated for each element of VECTOR point
- other than the regset header itself. The vector has NELTS elements. */
+static void
+notice_stack_pointer_modification (x, pat)
+ rtx x;
+ rtx pat ATTRIBUTE_UNUSED;
+{
+ if (x == stack_pointer_rtx
+ /* The stack pointer is only modified indirectly as the result
+ of a push until later in flow. See the comments in rtl.texi
+ regarding Embedded Side-Effects on Addresses. */
+ || (GET_CODE (x) == MEM
+ && (GET_CODE (XEXP (x, 0)) == PRE_DEC
+ || GET_CODE (XEXP (x, 0)) == PRE_INC
+ || GET_CODE (XEXP (x, 0)) == POST_DEC
+ || GET_CODE (XEXP (x, 0)) == POST_INC)
+ && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
+ current_function_sp_is_unchanging = 0;
+}
-void
-free_regset_vector (vector, nelts)
- regset *vector;
- int nelts;
+/* Record which insns refer to any volatile memory
+ or for any reason can't be deleted just because they are dead stores.
+ Also, delete any insns that copy a register to itself.
+ And see if the stack pointer is modified. */
+static void
+record_volatile_insns (f)
+ rtx f;
{
- register int i;
+ rtx insn;
+ for (insn = f; insn; insn = NEXT_INSN (insn))
+ {
+ enum rtx_code code1 = GET_CODE (insn);
+ if (code1 == CALL_INSN)
+ INSN_VOLATILE (insn) = 1;
+ else if (code1 == INSN || code1 == JUMP_INSN)
+ {
+ if (GET_CODE (PATTERN (insn)) != USE
+ && volatile_refs_p (PATTERN (insn)))
+ INSN_VOLATILE (insn) = 1;
- for (i = 0; i < nelts; i++)
- FREE_REG_SET (vector[i]);
+ /* A SET that makes space on the stack cannot be dead.
+ (Such SETs occur only for allocating variable-size data,
+ so they will always have a PLUS or MINUS according to the
+ direction of stack growth.)
+ Even if this function never uses this stack pointer value,
+ signal handlers do! */
+ else if (code1 == INSN && GET_CODE (PATTERN (insn)) == SET
+ && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
+#ifdef STACK_GROWS_DOWNWARD
+ && GET_CODE (SET_SRC (PATTERN (insn))) == MINUS
+#else
+ && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
+#endif
+ && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx)
+ INSN_VOLATILE (insn) = 1;
+
+ /* Delete (in effect) any obvious no-op moves. */
+ else if (noop_move_p (insn))
+ {
+ PUT_CODE (insn, NOTE);
+ NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
+ NOTE_SOURCE_FILE (insn) = 0;
+ }
+ }
+
+ /* Check if insn modifies the stack pointer. */
+ if ( current_function_sp_is_unchanging
+ && GET_RTX_CLASS (GET_CODE (insn)) == 'i')
+ note_stores (PATTERN (insn), notice_stack_pointer_modification);
+ }
}
-/* Compute the registers live at the beginning of a basic block
- from those live at the end.
+/* Mark those regs which are needed at the end of the function as live
+ at the end of the last basic block. */
+static void
+mark_regs_live_at_end (set)
+ regset set;
+{
+ int i;
+
+#ifdef EXIT_IGNORE_STACK
+ if (! EXIT_IGNORE_STACK
+ || (! FRAME_POINTER_REQUIRED
+ && ! current_function_calls_alloca
+ && flag_omit_frame_pointer)
+ || current_function_sp_is_unchanging)
+#endif
+ /* If exiting needs the right stack value,
+ consider the stack pointer live at the end of the function. */
+ SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
- When called, OLD contains those live at the end.
- On return, it contains those live at the beginning.
- FIRST and LAST are the first and last insns of the basic block.
+ /* Mark the frame pointer is needed at the end of the function. If
+ we end up eliminating it, it will be removed from the live list
+ of each basic block by reload. */
- FINAL is nonzero if we are doing the final pass which is not
- for computing the life info (since that has already been done)
- but for acting on it. On this pass, we delete dead stores,
- set up the logical links and dead-variables lists of instructions,
- and merge instructions for autoincrement and autodecrement addresses.
+ SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
+#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
+ /* If they are different, also mark the hard frame pointer as live */
+ SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
+#endif
- SIGNIFICANT is nonzero only the first time for each basic block.
- If it is nonzero, it points to a regset in which we store
- a 1 for each register that is set within the block.
- BNUM is the number of the basic block. */
+ /* Mark all global registers and all registers used by the epilogue
+ as being live at the end of the function since they may be
+ referenced by our caller. */
+ for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+ if (global_regs[i]
+#ifdef EPILOGUE_USES
+ || EPILOGUE_USES (i)
+#endif
+ )
+ SET_REGNO_REG_SET (set, i);
+}
+
+/* Determine which registers are live at the start of each
+ basic block of the function whose first insn is F.
+ NREGS is the number of registers used in F.
+ We allocate the vector basic_block_live_at_start
+ and the regsets that it points to, and fill them with the data.
+ regset_size and regset_bytes are also set here. */
static void
-propagate_block (old, first, last, final, significant, bnum)
- register regset old;
- rtx first;
- rtx last;
- int final;
- regset significant;
- int bnum;
+life_analysis_1 (f, nregs)
+ rtx f;
+ int nregs;
{
- register rtx insn;
- rtx prev;
- regset live;
- regset dead;
+ int first_pass;
+ int changed;
+ /* For each basic block, a bitmask of regs
+ live on exit from the block. */
+ regset *basic_block_live_at_end;
+ /* For each basic block, a bitmask of regs
+ live on entry to a successor-block of this block.
+ If this does not match basic_block_live_at_end,
+ that must be updated, and the block must be rescanned. */
+ regset *basic_block_new_live_at_end;
+ /* For each basic block, a bitmask of regs
+ whose liveness at the end of the basic block
+ can make a difference in which regs are live on entry to the block.
+ These are the regs that are set within the basic block,
+ possibly excluding those that are used after they are set. */
+ regset *basic_block_significant;
+ register int i;
+ char save_regs_ever_live[FIRST_PSEUDO_REGISTER];
- /* The following variables are used only if FINAL is nonzero. */
- /* This vector gets one element for each reg that has been live
- at any point in the basic block that has been scanned so far.
- SOMETIMES_MAX says how many elements are in use so far. */
- register int *regs_sometimes_live;
- int sometimes_max = 0;
- /* This regset has 1 for each reg that we have seen live so far.
- It and REGS_SOMETIMES_LIVE are updated together. */
- regset maxlive;
+ struct obstack flow_obstack;
- /* The loop depth may change in the middle of a basic block. Since we
- scan from end to beginning, we start with the depth at the end of the
- current basic block, and adjust as we pass ends and starts of loops. */
- loop_depth = basic_block_loop_depth[bnum];
+ gcc_obstack_init (&flow_obstack);
- dead = ALLOCA_REG_SET ();
- live = ALLOCA_REG_SET ();
+ max_regno = nregs;
- cc0_live = 0;
- last_mem_set = 0;
+ /* The post-reload life analysis have (on a global basis) the same registers
+ live as was computed by reload itself.
- /* Include any notes at the end of the block in the scan.
- This is in case the block ends with a call to setjmp. */
+ Otherwise elimination offsets and such may be incorrect.
- while (NEXT_INSN (last) != 0 && GET_CODE (NEXT_INSN (last)) == NOTE)
- {
- /* Look for loop boundaries, we are going forward here. */
- last = NEXT_INSN (last);
- if (NOTE_LINE_NUMBER (last) == NOTE_INSN_LOOP_BEG)
- loop_depth++;
- else if (NOTE_LINE_NUMBER (last) == NOTE_INSN_LOOP_END)
- loop_depth--;
- }
+ Reload will make some registers as live even though they do not appear
+ in the rtl. */
+ if (reload_completed)
+ bcopy (regs_ever_live, save_regs_ever_live, (sizeof (regs_ever_live)));
- if (final)
- {
- register int i;
+ bzero (regs_ever_live, sizeof regs_ever_live);
- num_scratch = 0;
- maxlive = ALLOCA_REG_SET ();
- COPY_REG_SET (maxlive, old);
- regs_sometimes_live = (int *) alloca (max_regno * sizeof (int));
+ /* Allocate and zero out many data structures
+ that will record the data from lifetime analysis. */
- /* Process the regs live at the end of the block.
- Enter them in MAXLIVE and REGS_SOMETIMES_LIVE.
- Also mark them as not local to any one basic block. */
- EXECUTE_IF_SET_IN_REG_SET (old, 0, i,
- {
- REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL;
- regs_sometimes_live[sometimes_max] = i;
- sometimes_max++;
- });
- }
+ allocate_for_life_analysis ();
- /* Scan the block an insn at a time from end to beginning. */
+ reg_next_use = (rtx *) alloca (nregs * sizeof (rtx));
+ bzero ((char *) reg_next_use, nregs * sizeof (rtx));
- for (insn = last; ; insn = prev)
- {
- prev = PREV_INSN (insn);
+ /* Set up several regset-vectors used internally within this function.
+ Their meanings are documented above, with their declarations. */
- if (GET_CODE (insn) == NOTE)
- {
- /* Look for loop boundaries, remembering that we are going
- backwards. */
- if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
- loop_depth++;
- else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
- loop_depth--;
+ basic_block_live_at_end
+ = (regset *) alloca (n_basic_blocks * sizeof (regset));
- /* If we have LOOP_DEPTH == 0, there has been a bookkeeping error.
- Abort now rather than setting register status incorrectly. */
- if (loop_depth == 0)
- abort ();
+ /* Don't use alloca since that leads to a crash rather than an error message
+ if there isn't enough space.
+ Don't use oballoc since we may need to allocate other things during
+ this function on the temporary obstack. */
+ init_regset_vector (basic_block_live_at_end, n_basic_blocks, &flow_obstack);
- /* If this is a call to `setjmp' et al,
- warn if any non-volatile datum is live. */
+ basic_block_new_live_at_end
+ = (regset *) alloca (n_basic_blocks * sizeof (regset));
+ init_regset_vector (basic_block_new_live_at_end, n_basic_blocks,
+ &flow_obstack);
- if (final && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP)
- IOR_REG_SET (regs_live_at_setjmp, old);
- }
+ basic_block_significant
+ = (regset *) alloca (n_basic_blocks * sizeof (regset));
+ init_regset_vector (basic_block_significant, n_basic_blocks, &flow_obstack);
- /* Update the life-status of regs for this insn.
- First DEAD gets which regs are set in this insn
- then LIVE gets which regs are used in this insn.
- Then the regs live before the insn
- are those live after, with DEAD regs turned off,
- and then LIVE regs turned on. */
+ /* Assume that the stack pointer is unchanging if alloca hasn't been used.
+ This will be cleared by record_volatile_insns if it encounters an insn
+ which modifies the stack pointer. */
+ current_function_sp_is_unchanging = !current_function_calls_alloca;
- else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
+ record_volatile_insns (f);
+
+ if (n_basic_blocks > 0)
+ {
+ mark_regs_live_at_end (basic_block_live_at_end[n_basic_blocks - 1]);
+ COPY_REG_SET (basic_block_new_live_at_end[n_basic_blocks - 1],
+ basic_block_live_at_end[n_basic_blocks - 1]);
+ }
+
+ /* Propagate life info through the basic blocks
+ around the graph of basic blocks.
+
+ This is a relaxation process: each time a new register
+ is live at the end of the basic block, we must scan the block
+ to determine which registers are, as a consequence, live at the beginning
+ of that block. These registers must then be marked live at the ends
+ of all the blocks that can transfer control to that block.
+ The process continues until it reaches a fixed point. */
+
+ first_pass = 1;
+ changed = 1;
+ while (changed)
+ {
+ changed = 0;
+ for (i = n_basic_blocks - 1; i >= 0; i--)
{
- register int i;
- rtx note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
- int insn_is_dead
- = (insn_dead_p (PATTERN (insn), old, 0)
- /* Don't delete something that refers to volatile storage! */
- && ! INSN_VOLATILE (insn));
- int libcall_is_dead
- = (insn_is_dead && note != 0
- && libcall_dead_p (PATTERN (insn), old, note, insn));
+ int consider = first_pass;
+ int must_rescan = first_pass;
+ register int j;
- /* If an instruction consists of just dead store(s) on final pass,
- "delete" it by turning it into a NOTE of type NOTE_INSN_DELETED.
- We could really delete it with delete_insn, but that
- can cause trouble for first or last insn in a basic block. */
- if (final && insn_is_dead)
+ if (!first_pass)
{
- PUT_CODE (insn, NOTE);
- NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (insn) = 0;
-
- /* CC0 is now known to be dead. Either this insn used it,
- in which case it doesn't anymore, or clobbered it,
- so the next insn can't use it. */
- cc0_live = 0;
+ /* Set CONSIDER if this block needs thinking about at all
+ (that is, if the regs live now at the end of it
+ are not the same as were live at the end of it when
+ we last thought about it).
+ Set must_rescan if it needs to be thought about
+ instruction by instruction (that is, if any additional
+ reg that is live at the end now but was not live there before
+ is one of the significant regs of this basic block). */
- /* If this insn is copying the return value from a library call,
- delete the entire library call. */
- if (libcall_is_dead)
- {
- rtx first = XEXP (note, 0);
- rtx p = insn;
- while (INSN_DELETED_P (first))
- first = NEXT_INSN (first);
- while (p != first)
- {
- p = PREV_INSN (p);
- PUT_CODE (p, NOTE);
- NOTE_LINE_NUMBER (p) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (p) = 0;
- }
- }
- goto flushed;
+ EXECUTE_IF_AND_COMPL_IN_REG_SET
+ (basic_block_new_live_at_end[i],
+ basic_block_live_at_end[i], 0, j,
+ {
+ consider = 1;
+ if (REGNO_REG_SET_P (basic_block_significant[i], j))
+ {
+ must_rescan = 1;
+ goto done;
+ }
+ });
+ done:
+ if (! consider)
+ continue;
}
- CLEAR_REG_SET (dead);
- CLEAR_REG_SET (live);
-
- /* See if this is an increment or decrement that can be
- merged into a following memory address. */
-#ifdef AUTO_INC_DEC
- {
- register rtx x = PATTERN (insn);
- /* Does this instruction increment or decrement a register? */
- if (final && GET_CODE (x) == SET
- && GET_CODE (SET_DEST (x)) == REG
- && (GET_CODE (SET_SRC (x)) == PLUS
- || GET_CODE (SET_SRC (x)) == MINUS)
- && XEXP (SET_SRC (x), 0) == SET_DEST (x)
- && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
- /* Ok, look for a following memory ref we can combine with.
- If one is found, change the memory ref to a PRE_INC
- or PRE_DEC, cancel this insn, and return 1.
- Return 0 if nothing has been done. */
- && try_pre_increment_1 (insn))
- goto flushed;
- }
-#endif /* AUTO_INC_DEC */
+ /* The live_at_start of this block may be changing,
+ so another pass will be required after this one. */
+ changed = 1;
- /* If this is not the final pass, and this insn is copying the
- value of a library call and it's dead, don't scan the
- insns that perform the library call, so that the call's
- arguments are not marked live. */
- if (libcall_is_dead)
+ if (! must_rescan)
{
- /* Mark the dest reg as `significant'. */
- mark_set_regs (old, dead, PATTERN (insn), NULL_RTX, significant);
+ /* No complete rescan needed;
+ just record those variables newly known live at end
+ as live at start as well. */
+ IOR_AND_COMPL_REG_SET (basic_block_live_at_start[i],
+ basic_block_new_live_at_end[i],
+ basic_block_live_at_end[i]);
- insn = XEXP (note, 0);
- prev = PREV_INSN (insn);
+ IOR_AND_COMPL_REG_SET (basic_block_live_at_end[i],
+ basic_block_new_live_at_end[i],
+ basic_block_live_at_end[i]);
}
- else if (GET_CODE (PATTERN (insn)) == SET
- && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
- && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
- && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
- && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
- /* We have an insn to pop a constant amount off the stack.
- (Such insns use PLUS regardless of the direction of the stack,
- and any insn to adjust the stack by a constant is always a pop.)
- These insns, if not dead stores, have no effect on life. */
- ;
else
{
- /* LIVE gets the regs used in INSN;
- DEAD gets those set by it. Dead insns don't make anything
- live. */
-
- mark_set_regs (old, dead, PATTERN (insn),
- final ? insn : NULL_RTX, significant);
-
- /* If an insn doesn't use CC0, it becomes dead since we
- assume that every insn clobbers it. So show it dead here;
- mark_used_regs will set it live if it is referenced. */
- cc0_live = 0;
+ /* Update the basic_block_live_at_start
+ by propagation backwards through the block. */
+ COPY_REG_SET (basic_block_live_at_end[i],
+ basic_block_new_live_at_end[i]);
+ COPY_REG_SET (basic_block_live_at_start[i],
+ basic_block_live_at_end[i]);
+ propagate_block (basic_block_live_at_start[i],
+ basic_block_head[i], basic_block_end[i], 0,
+ first_pass ? basic_block_significant[i]
+ : (regset) 0,
+ i);
+ }
- if (! insn_is_dead)
- mark_used_regs (old, live, PATTERN (insn), final, insn);
+ {
+ int_list_ptr p;
- /* Sometimes we may have inserted something before INSN (such as
- a move) when we make an auto-inc. So ensure we will scan
- those insns. */
-#ifdef AUTO_INC_DEC
- prev = PREV_INSN (insn);
+ /* Update the basic_block_new_live_at_end's of
+ all the blocks that reach this one. */
+ for (p = basic_block_pred[i]; p; p = p->next)
+ {
+ register int from_block = INT_LIST_VAL (p);
+ IOR_REG_SET (basic_block_new_live_at_end[from_block],
+ basic_block_live_at_start[i]);
+ }
+ }
+#ifdef USE_C_ALLOCA
+ alloca (0);
#endif
+ }
+ first_pass = 0;
+ }
- if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
- {
- register int i;
-
- rtx note;
+ /* The only pseudos that are live at the beginning of the function are
+ those that were not set anywhere in the function. local-alloc doesn't
+ know how to handle these correctly, so mark them as not local to any
+ one basic block. */
- for (note = CALL_INSN_FUNCTION_USAGE (insn);
- note;
- note = XEXP (note, 1))
- if (GET_CODE (XEXP (note, 0)) == USE)
- mark_used_regs (old, live, SET_DEST (XEXP (note, 0)),
- final, insn);
+ if (n_basic_blocks > 0)
+ EXECUTE_IF_SET_IN_REG_SET (basic_block_live_at_start[0],
+ FIRST_PSEUDO_REGISTER, i,
+ {
+ REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL;
+ });
- /* Each call clobbers all call-clobbered regs that are not
- global or fixed. Note that the function-value reg is a
- call-clobbered reg, and mark_set_regs has already had
- a chance to handle it. */
+ /* Now the life information is accurate.
+ Make one more pass over each basic block
+ to delete dead stores, create autoincrement addressing
+ and record how many times each register is used, is set, or dies.
- for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
- if (call_used_regs[i] && ! global_regs[i]
- && ! fixed_regs[i])
- SET_REGNO_REG_SET (dead, i);
+ To save time, we operate directly in basic_block_live_at_end[i],
+ thus destroying it (in fact, converting it into a copy of
+ basic_block_live_at_start[i]). This is ok now because
+ basic_block_live_at_end[i] is no longer used past this point. */
- /* The stack ptr is used (honorarily) by a CALL insn. */
- SET_REGNO_REG_SET (live, STACK_POINTER_REGNUM);
+ for (i = 0; i < n_basic_blocks; i++)
+ {
+ propagate_block (basic_block_live_at_end[i],
+ basic_block_head[i], basic_block_end[i], 1,
+ (regset) 0, i);
+#ifdef USE_C_ALLOCA
+ alloca (0);
+#endif
+ }
- /* Calls may also reference any of the global registers,
- so they are made live. */
- for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
- if (global_regs[i])
- mark_used_regs (old, live,
- gen_rtx (REG, reg_raw_mode[i], i),
- final, insn);
+#if 0
+ /* Something live during a setjmp should not be put in a register
+ on certain machines which restore regs from stack frames
+ rather than from the jmpbuf.
+ But we don't need to do this for the user's variables, since
+ ANSI says only volatile variables need this. */
+#ifdef LONGJMP_RESTORE_FROM_STACK
+ EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
+ FIRST_PSEUDO_REGISTER, i,
+ {
+ if (regno_reg_rtx[i] != 0
+ && ! REG_USERVAR_P (regno_reg_rtx[i]))
+ {
+ REG_LIVE_LENGTH (i) = -1;
+ REG_BASIC_BLOCK (i) = -1;
+ }
+ });
+#endif
+#endif
- /* Calls also clobber memory. */
- last_mem_set = 0;
- }
-
- /* Update OLD for the registers used or set. */
- AND_COMPL_REG_SET (old, dead);
- IOR_REG_SET (old, live);
+ /* We have a problem with any pseudoreg that
+ lives across the setjmp. ANSI says that if a
+ user variable does not change in value
+ between the setjmp and the longjmp, then the longjmp preserves it.
+ This includes longjmp from a place where the pseudo appears dead.
+ (In principle, the value still exists if it is in scope.)
+ If the pseudo goes in a hard reg, some other value may occupy
+ that hard reg where this pseudo is dead, thus clobbering the pseudo.
+ Conclusion: such a pseudo must not go in a hard reg. */
+ EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
+ FIRST_PSEUDO_REGISTER, i,
+ {
+ if (regno_reg_rtx[i] != 0)
+ {
+ REG_LIVE_LENGTH (i) = -1;
+ REG_BASIC_BLOCK (i) = -1;
+ }
+ });
- if (GET_CODE (insn) == CALL_INSN && final)
- {
- /* Any regs live at the time of a call instruction
- must not go in a register clobbered by calls.
- Find all regs now live and record this for them. */
+ /* Restore regs_ever_live that was provided by reload. */
+ if (reload_completed)
+ bcopy (save_regs_ever_live, regs_ever_live, (sizeof (regs_ever_live)));
- register int *p = regs_sometimes_live;
+ free_regset_vector (basic_block_live_at_end, n_basic_blocks);
+ free_regset_vector (basic_block_new_live_at_end, n_basic_blocks);
+ free_regset_vector (basic_block_significant, n_basic_blocks);
+ basic_block_live_at_end = (regset *)0;
+ basic_block_new_live_at_end = (regset *)0;
+ basic_block_significant = (regset *)0;
- for (i = 0; i < sometimes_max; i++, p++)
- if (REGNO_REG_SET_P (old, *p))
- REG_N_CALLS_CROSSED (*p)++;
- }
- }
+ obstack_free (&flow_obstack, NULL_PTR);
+}
+\f
+/* Subroutines of life analysis. */
- /* On final pass, add any additional sometimes-live regs
- into MAXLIVE and REGS_SOMETIMES_LIVE.
- Also update counts of how many insns each reg is live at. */
+/* Allocate the permanent data structures that represent the results
+ of life analysis. Not static since used also for stupid life analysis. */
- if (final)
- {
- register int regno;
- register int *p;
+void
+allocate_for_life_analysis ()
+{
+ register int i;
- EXECUTE_IF_AND_COMPL_IN_REG_SET
- (live, maxlive, 0, regno,
- {
- regs_sometimes_live[sometimes_max++] = regno;
- SET_REGNO_REG_SET (maxlive, regno);
- });
+ /* Recalculate the register space, in case it has grown. Old style
+ vector oriented regsets would set regset_{size,bytes} here also. */
+ allocate_reg_info (max_regno, FALSE, FALSE);
- p = regs_sometimes_live;
- for (i = 0; i < sometimes_max; i++)
- {
- regno = *p++;
- if (REGNO_REG_SET_P (old, regno))
- REG_LIVE_LENGTH (regno)++;
- }
- }
- }
- flushed: ;
- if (insn == first)
- break;
- }
+ /* Because both reg_scan and flow_analysis want to set up the REG_N_SETS
+ information, explicitly reset it here. The allocation should have
+ already happened on the previous reg_scan pass. Make sure in case
+ some more registers were allocated. */
+ for (i = 0; i < max_regno; i++)
+ REG_N_SETS (i) = 0;
- FREE_REG_SET (dead);
- FREE_REG_SET (live);
- if (final)
- FREE_REG_SET (maxlive);
+ basic_block_live_at_start
+ = (regset *) oballoc (n_basic_blocks * sizeof (regset));
+ init_regset_vector (basic_block_live_at_start, n_basic_blocks,
+ function_obstack);
- if (num_scratch > max_scratch)
- max_scratch = num_scratch;
+ regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (function_obstack);
+ CLEAR_REG_SET (regs_live_at_setjmp);
}
-\f
-/* Return 1 if X (the body of an insn, or part of it) is just dead stores
- (SET expressions whose destinations are registers dead after the insn).
- NEEDED is the regset that says which regs are alive after the insn.
- Unless CALL_OK is non-zero, an insn is needed if it contains a CALL. */
+/* Make each element of VECTOR point at a regset. The vector has
+ NELTS elements, and space is allocated from the ALLOC_OBSTACK
+ obstack. */
-static int
-insn_dead_p (x, needed, call_ok)
- rtx x;
- regset needed;
- int call_ok;
+static void
+init_regset_vector (vector, nelts, alloc_obstack)
+ regset *vector;
+ int nelts;
+ struct obstack *alloc_obstack;
{
- register RTX_CODE code = GET_CODE (x);
- /* If setting something that's a reg or part of one,
- see if that register's altered value will be live. */
+ register int i;
- if (code == SET)
+ for (i = 0; i < nelts; i++)
{
- register rtx r = SET_DEST (x);
- /* A SET that is a subroutine call cannot be dead. */
- if (! call_ok && GET_CODE (SET_SRC (x)) == CALL)
- return 0;
+ vector[i] = OBSTACK_ALLOC_REG_SET (alloc_obstack);
+ CLEAR_REG_SET (vector[i]);
+ }
+}
-#ifdef HAVE_cc0
- if (GET_CODE (r) == CC0)
- return ! cc0_live;
-#endif
-
- if (GET_CODE (r) == MEM && last_mem_set && ! MEM_VOLATILE_P (r)
- && rtx_equal_p (r, last_mem_set))
- return 1;
+/* Release any additional space allocated for each element of VECTOR point
+ other than the regset header itself. The vector has NELTS elements. */
- while (GET_CODE (r) == SUBREG
- || GET_CODE (r) == STRICT_LOW_PART
- || GET_CODE (r) == ZERO_EXTRACT
- || GET_CODE (r) == SIGN_EXTRACT)
- r = SUBREG_REG (r);
+void
+free_regset_vector (vector, nelts)
+ regset *vector;
+ int nelts;
+{
+ register int i;
- if (GET_CODE (r) == REG)
- {
- register int regno = REGNO (r);
+ for (i = 0; i < nelts; i++)
+ FREE_REG_SET (vector[i]);
+}
- /* Don't delete insns to set global regs. */
- if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
- /* Make sure insns to set frame pointer aren't deleted. */
- || regno == FRAME_POINTER_REGNUM
-#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
- || regno == HARD_FRAME_POINTER_REGNUM
-#endif
-#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
- /* Make sure insns to set arg pointer are never deleted
- (if the arg pointer isn't fixed, there will be a USE for
- it, so we can treat it normally). */
- || (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
-#endif
- || REGNO_REG_SET_P (needed, regno))
- return 0;
+/* Compute the registers live at the beginning of a basic block
+ from those live at the end.
- /* If this is a hard register, verify that subsequent words are
- not needed. */
- if (regno < FIRST_PSEUDO_REGISTER)
- {
- int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
+ When called, OLD contains those live at the end.
+ On return, it contains those live at the beginning.
+ FIRST and LAST are the first and last insns of the basic block.
- while (--n > 0)
- if (REGNO_REG_SET_P (needed, regno+n))
- return 0;
- }
+ FINAL is nonzero if we are doing the final pass which is not
+ for computing the life info (since that has already been done)
+ but for acting on it. On this pass, we delete dead stores,
+ set up the logical links and dead-variables lists of instructions,
+ and merge instructions for autoincrement and autodecrement addresses.
- return 1;
- }
- }
- /* If performing several activities,
- insn is dead if each activity is individually dead.
- Also, CLOBBERs and USEs can be ignored; a CLOBBER or USE
- that's inside a PARALLEL doesn't make the insn worth keeping. */
- else if (code == PARALLEL)
- {
- register int i = XVECLEN (x, 0);
- for (i--; i >= 0; i--)
- {
- rtx elt = XVECEXP (x, 0, i);
- if (!insn_dead_p (elt, needed, call_ok)
- && GET_CODE (elt) != CLOBBER
- && GET_CODE (elt) != USE)
- return 0;
- }
- return 1;
- }
- /* We do not check CLOBBER or USE here.
- An insn consisting of just a CLOBBER or just a USE
- should not be deleted. */
- return 0;
-}
+ SIGNIFICANT is nonzero only the first time for each basic block.
+ If it is nonzero, it points to a regset in which we store
+ a 1 for each register that is set within the block.
-/* If X is the pattern of the last insn in a libcall, and assuming X is dead,
- return 1 if the entire library call is dead.
- This is true if X copies a register (hard or pseudo)
- and if the hard return reg of the call insn is dead.
- (The caller should have tested the destination of X already for death.)
+ BNUM is the number of the basic block. */
- If this insn doesn't just copy a register, then we don't
- have an ordinary libcall. In that case, cse could not have
- managed to substitute the source for the dest later on,
- so we can assume the libcall is dead.
+static void
+propagate_block (old, first, last, final, significant, bnum)
+ register regset old;
+ rtx first;
+ rtx last;
+ int final;
+ regset significant;
+ int bnum;
+{
+ register rtx insn;
+ rtx prev;
+ regset live;
+ regset dead;
- NEEDED is the bit vector of pseudoregs live before this insn.
- NOTE is the REG_RETVAL note of the insn. INSN is the insn itself. */
+ /* The loop depth may change in the middle of a basic block. Since we
+ scan from end to beginning, we start with the depth at the end of the
+ current basic block, and adjust as we pass ends and starts of loops. */
+ loop_depth = basic_block_loop_depth[bnum];
-static int
-libcall_dead_p (x, needed, note, insn)
- rtx x;
- regset needed;
- rtx note;
- rtx insn;
-{
- register RTX_CODE code = GET_CODE (x);
+ dead = ALLOCA_REG_SET ();
+ live = ALLOCA_REG_SET ();
- if (code == SET)
+ cc0_live = 0;
+ last_mem_set = 0;
+
+ /* Include any notes at the end of the block in the scan.
+ This is in case the block ends with a call to setjmp. */
+
+ while (NEXT_INSN (last) != 0 && GET_CODE (NEXT_INSN (last)) == NOTE)
{
- register rtx r = SET_SRC (x);
- if (GET_CODE (r) == REG)
- {
- rtx call = XEXP (note, 0);
- register int i;
+ /* Look for loop boundaries, we are going forward here. */
+ last = NEXT_INSN (last);
+ if (NOTE_LINE_NUMBER (last) == NOTE_INSN_LOOP_BEG)
+ loop_depth++;
+ else if (NOTE_LINE_NUMBER (last) == NOTE_INSN_LOOP_END)
+ loop_depth--;
+ }
- /* Find the call insn. */
- while (call != insn && GET_CODE (call) != CALL_INSN)
- call = NEXT_INSN (call);
+ if (final)
+ {
+ register int i;
- /* If there is none, do nothing special,
- since ordinary death handling can understand these insns. */
- if (call == insn)
- return 0;
+ /* Process the regs live at the end of the block.
+ Mark them as not local to any one basic block. */
+ EXECUTE_IF_SET_IN_REG_SET (old, 0, i,
+ {
+ REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL;
+ });
+ }
- /* See if the hard reg holding the value is dead.
- If this is a PARALLEL, find the call within it. */
- call = PATTERN (call);
- if (GET_CODE (call) == PARALLEL)
- {
- for (i = XVECLEN (call, 0) - 1; i >= 0; i--)
- if (GET_CODE (XVECEXP (call, 0, i)) == SET
- && GET_CODE (SET_SRC (XVECEXP (call, 0, i))) == CALL)
- break;
+ /* Scan the block an insn at a time from end to beginning. */
- /* This may be a library call that is returning a value
- via invisible pointer. Do nothing special, since
- ordinary death handling can understand these insns. */
- if (i < 0)
- return 0;
+ for (insn = last; ; insn = prev)
+ {
+ prev = PREV_INSN (insn);
- call = XVECEXP (call, 0, i);
- }
+ if (GET_CODE (insn) == NOTE)
+ {
+ /* Look for loop boundaries, remembering that we are going
+ backwards. */
+ if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
+ loop_depth++;
+ else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
+ loop_depth--;
- return insn_dead_p (call, needed, 1);
+ /* If we have LOOP_DEPTH == 0, there has been a bookkeeping error.
+ Abort now rather than setting register status incorrectly. */
+ if (loop_depth == 0)
+ abort ();
+
+ /* If this is a call to `setjmp' et al,
+ warn if any non-volatile datum is live. */
+
+ if (final && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP)
+ IOR_REG_SET (regs_live_at_setjmp, old);
}
- }
- return 1;
-}
-/* Return 1 if register REGNO was used before it was set.
- In other words, if it is live at function entry.
- Don't count global register variables or variables in registers
- that can be used for function arg passing, though. */
+ /* Update the life-status of regs for this insn.
+ First DEAD gets which regs are set in this insn
+ then LIVE gets which regs are used in this insn.
+ Then the regs live before the insn
+ are those live after, with DEAD regs turned off,
+ and then LIVE regs turned on. */
-int
-regno_uninitialized (regno)
- int regno;
-{
- if (n_basic_blocks == 0
- || (regno < FIRST_PSEUDO_REGISTER
- && (global_regs[regno] || FUNCTION_ARG_REGNO_P (regno))))
- return 0;
+ else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
+ {
+ register int i;
+ rtx note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
+ int insn_is_dead
+ = (insn_dead_p (PATTERN (insn), old, 0)
+ /* Don't delete something that refers to volatile storage! */
+ && ! INSN_VOLATILE (insn));
+ int libcall_is_dead
+ = (insn_is_dead && note != 0
+ && libcall_dead_p (PATTERN (insn), old, note, insn));
- return REGNO_REG_SET_P (basic_block_live_at_start[0], regno);
-}
+ /* If an instruction consists of just dead store(s) on final pass,
+ "delete" it by turning it into a NOTE of type NOTE_INSN_DELETED.
+ We could really delete it with delete_insn, but that
+ can cause trouble for first or last insn in a basic block. */
+ if (final && insn_is_dead)
+ {
+ PUT_CODE (insn, NOTE);
+ NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
+ NOTE_SOURCE_FILE (insn) = 0;
-/* 1 if register REGNO was alive at a place where `setjmp' was called
- and was set more than once or is an argument.
- Such regs may be clobbered by `longjmp'. */
+ /* CC0 is now known to be dead. Either this insn used it,
+ in which case it doesn't anymore, or clobbered it,
+ so the next insn can't use it. */
+ cc0_live = 0;
-int
-regno_clobbered_at_setjmp (regno)
- int regno;
-{
- if (n_basic_blocks == 0)
- return 0;
+ /* If this insn is copying the return value from a library call,
+ delete the entire library call. */
+ if (libcall_is_dead)
+ {
+ rtx first = XEXP (note, 0);
+ rtx p = insn;
+ while (INSN_DELETED_P (first))
+ first = NEXT_INSN (first);
+ while (p != first)
+ {
+ p = PREV_INSN (p);
+ PUT_CODE (p, NOTE);
+ NOTE_LINE_NUMBER (p) = NOTE_INSN_DELETED;
+ NOTE_SOURCE_FILE (p) = 0;
+ }
+ }
+ goto flushed;
+ }
- return ((REG_N_SETS (regno) > 1
- || REGNO_REG_SET_P (basic_block_live_at_start[0], regno))
- && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
-}
-\f
-/* Process the registers that are set within X.
- Their bits are set to 1 in the regset DEAD,
- because they are dead prior to this insn.
+ CLEAR_REG_SET (dead);
+ CLEAR_REG_SET (live);
- If INSN is nonzero, it is the insn being processed
- and the fact that it is nonzero implies this is the FINAL pass
- in propagate_block. In this case, various info about register
- usage is stored, LOG_LINKS fields of insns are set up. */
+ /* See if this is an increment or decrement that can be
+ merged into a following memory address. */
+#ifdef AUTO_INC_DEC
+ {
+ register rtx x = single_set (insn);
-static void
-mark_set_regs (needed, dead, x, insn, significant)
- regset needed;
- regset dead;
- rtx x;
- rtx insn;
- regset significant;
-{
- register RTX_CODE code = GET_CODE (x);
+ /* Does this instruction increment or decrement a register? */
+ if (!reload_completed
+ && final && x != 0
+ && GET_CODE (SET_DEST (x)) == REG
+ && (GET_CODE (SET_SRC (x)) == PLUS
+ || GET_CODE (SET_SRC (x)) == MINUS)
+ && XEXP (SET_SRC (x), 0) == SET_DEST (x)
+ && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
+ /* Ok, look for a following memory ref we can combine with.
+ If one is found, change the memory ref to a PRE_INC
+ or PRE_DEC, cancel this insn, and return 1.
+ Return 0 if nothing has been done. */
+ && try_pre_increment_1 (insn))
+ goto flushed;
+ }
+#endif /* AUTO_INC_DEC */
- if (code == SET || code == CLOBBER)
- mark_set_1 (needed, dead, x, insn, significant);
- else if (code == PARALLEL)
- {
- register int i;
- for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
- {
- code = GET_CODE (XVECEXP (x, 0, i));
- if (code == SET || code == CLOBBER)
- mark_set_1 (needed, dead, XVECEXP (x, 0, i), insn, significant);
- }
- }
-}
+ /* If this is not the final pass, and this insn is copying the
+ value of a library call and it's dead, don't scan the
+ insns that perform the library call, so that the call's
+ arguments are not marked live. */
+ if (libcall_is_dead)
+ {
+ /* Mark the dest reg as `significant'. */
+ mark_set_regs (old, dead, PATTERN (insn), NULL_RTX, significant);
-/* Process a single SET rtx, X. */
+ insn = XEXP (note, 0);
+ prev = PREV_INSN (insn);
+ }
+ else if (GET_CODE (PATTERN (insn)) == SET
+ && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
+ && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
+ && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
+ && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
+ /* We have an insn to pop a constant amount off the stack.
+ (Such insns use PLUS regardless of the direction of the stack,
+ and any insn to adjust the stack by a constant is always a pop.)
+ These insns, if not dead stores, have no effect on life. */
+ ;
+ else
+ {
+ /* Any regs live at the time of a call instruction
+ must not go in a register clobbered by calls.
+ Find all regs now live and record this for them. */
-static void
-mark_set_1 (needed, dead, x, insn, significant)
- regset needed;
- regset dead;
- rtx x;
- rtx insn;
- regset significant;
-{
- register int regno;
- register rtx reg = SET_DEST (x);
+ if (GET_CODE (insn) == CALL_INSN && final)
+ EXECUTE_IF_SET_IN_REG_SET (old, 0, i,
+ {
+ REG_N_CALLS_CROSSED (i)++;
+ });
- /* Modifying just one hardware register of a multi-reg value
- or just a byte field of a register
- does not mean the value from before this insn is now dead.
- But it does mean liveness of that register at the end of the block
- is significant.
+ /* LIVE gets the regs used in INSN;
+ DEAD gets those set by it. Dead insns don't make anything
+ live. */
- Within mark_set_1, however, we treat it as if the register is
- indeed modified. mark_used_regs will, however, also treat this
- register as being used. Thus, we treat these insns as setting a
- new value for the register as a function of its old value. This
- cases LOG_LINKS to be made appropriately and this will help combine. */
+ mark_set_regs (old, dead, PATTERN (insn),
+ final ? insn : NULL_RTX, significant);
- while (GET_CODE (reg) == SUBREG || GET_CODE (reg) == ZERO_EXTRACT
- || GET_CODE (reg) == SIGN_EXTRACT
- || GET_CODE (reg) == STRICT_LOW_PART)
- reg = XEXP (reg, 0);
+ /* If an insn doesn't use CC0, it becomes dead since we
+ assume that every insn clobbers it. So show it dead here;
+ mark_used_regs will set it live if it is referenced. */
+ cc0_live = 0;
- /* If we are writing into memory or into a register mentioned in the
- address of the last thing stored into memory, show we don't know
- what the last store was. If we are writing memory, save the address
- unless it is volatile. */
- if (GET_CODE (reg) == MEM
- || (GET_CODE (reg) == REG
- && last_mem_set != 0 && reg_overlap_mentioned_p (reg, last_mem_set)))
- last_mem_set = 0;
-
- if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
- /* There are no REG_INC notes for SP, so we can't assume we'll see
- everything that invalidates it. To be safe, don't eliminate any
- stores though SP; none of them should be redundant anyway. */
- && ! reg_mentioned_p (stack_pointer_rtx, reg))
- last_mem_set = reg;
+ if (! insn_is_dead)
+ mark_used_regs (old, live, PATTERN (insn), final, insn);
- if (GET_CODE (reg) == REG
- && (regno = REGNO (reg), regno != FRAME_POINTER_REGNUM)
-#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
- && regno != HARD_FRAME_POINTER_REGNUM
-#endif
-#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
- && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
+ /* Sometimes we may have inserted something before INSN (such as
+ a move) when we make an auto-inc. So ensure we will scan
+ those insns. */
+#ifdef AUTO_INC_DEC
+ prev = PREV_INSN (insn);
#endif
- && ! (regno < FIRST_PSEUDO_REGISTER && global_regs[regno]))
- /* && regno != STACK_POINTER_REGNUM) -- let's try without this. */
- {
- int some_needed = REGNO_REG_SET_P (needed, regno);
- int some_not_needed = ! some_needed;
- /* Mark it as a significant register for this basic block. */
- if (significant)
- SET_REGNO_REG_SET (significant, regno);
+ if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
+ {
+ register int i;
- /* Mark it as as dead before this insn. */
- SET_REGNO_REG_SET (dead, regno);
+ rtx note;
- /* A hard reg in a wide mode may really be multiple registers.
- If so, mark all of them just like the first. */
- if (regno < FIRST_PSEUDO_REGISTER)
- {
- int n;
+ for (note = CALL_INSN_FUNCTION_USAGE (insn);
+ note;
+ note = XEXP (note, 1))
+ if (GET_CODE (XEXP (note, 0)) == USE)
+ mark_used_regs (old, live, SET_DEST (XEXP (note, 0)),
+ final, insn);
- /* Nothing below is needed for the stack pointer; get out asap.
- Eg, log links aren't needed, since combine won't use them. */
- if (regno == STACK_POINTER_REGNUM)
- return;
+ /* Each call clobbers all call-clobbered regs that are not
+ global or fixed. Note that the function-value reg is a
+ call-clobbered reg, and mark_set_regs has already had
+ a chance to handle it. */
- n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
- while (--n > 0)
- {
- int regno_n = regno + n;
- int needed_regno = REGNO_REG_SET_P (needed, regno_n);
- if (significant)
- SET_REGNO_REG_SET (significant, regno_n);
+ for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+ if (call_used_regs[i] && ! global_regs[i]
+ && ! fixed_regs[i])
+ SET_REGNO_REG_SET (dead, i);
+
+ /* The stack ptr is used (honorarily) by a CALL insn. */
+ SET_REGNO_REG_SET (live, STACK_POINTER_REGNUM);
+
+ /* Calls may also reference any of the global registers,
+ so they are made live. */
+ for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+ if (global_regs[i])
+ mark_used_regs (old, live,
+ gen_rtx_REG (reg_raw_mode[i], i),
+ final, insn);
+
+ /* Calls also clobber memory. */
+ last_mem_set = 0;
+ }
+
+ /* Update OLD for the registers used or set. */
+ AND_COMPL_REG_SET (old, dead);
+ IOR_REG_SET (old, live);
- SET_REGNO_REG_SET (dead, regno_n);
- some_needed |= needed_regno;
- some_not_needed |= ! needed_regno;
}
+
+ /* On final pass, update counts of how many insns each reg is live
+ at. */
+ if (final)
+ EXECUTE_IF_SET_IN_REG_SET (old, 0, i,
+ { REG_LIVE_LENGTH (i)++; });
}
- /* Additional data to record if this is the final pass. */
- if (insn)
- {
- register rtx y = reg_next_use[regno];
- register int blocknum = BLOCK_NUM (insn);
+ flushed: ;
+ if (insn == first)
+ break;
+ }
- /* If this is a hard reg, record this function uses the reg. */
+ FREE_REG_SET (dead);
+ FREE_REG_SET (live);
+}
+\f
+/* Return 1 if X (the body of an insn, or part of it) is just dead stores
+ (SET expressions whose destinations are registers dead after the insn).
+ NEEDED is the regset that says which regs are alive after the insn.
- if (regno < FIRST_PSEUDO_REGISTER)
- {
- register int i;
- int endregno = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg));
+ Unless CALL_OK is non-zero, an insn is needed if it contains a CALL. */
- for (i = regno; i < endregno; i++)
- {
- /* The next use is no longer "next", since a store
- intervenes. */
- reg_next_use[i] = 0;
+static int
+insn_dead_p (x, needed, call_ok)
+ rtx x;
+ regset needed;
+ int call_ok;
+{
+ enum rtx_code code = GET_CODE (x);
- regs_ever_live[i] = 1;
- REG_N_SETS (i)++;
- }
- }
- else
- {
- /* The next use is no longer "next", since a store
- intervenes. */
- reg_next_use[regno] = 0;
+ /* If setting something that's a reg or part of one,
+ see if that register's altered value will be live. */
- /* Keep track of which basic blocks each reg appears in. */
+ if (code == SET)
+ {
+ rtx r = SET_DEST (x);
- if (REG_BASIC_BLOCK (regno) == REG_BLOCK_UNKNOWN)
- REG_BASIC_BLOCK (regno) = blocknum;
- else if (REG_BASIC_BLOCK (regno) != blocknum)
- REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL;
+ /* A SET that is a subroutine call cannot be dead. */
+ if (! call_ok && GET_CODE (SET_SRC (x)) == CALL)
+ return 0;
- /* Count (weighted) references, stores, etc. This counts a
- register twice if it is modified, but that is correct. */
- REG_N_SETS (regno)++;
+#ifdef HAVE_cc0
+ if (GET_CODE (r) == CC0)
+ return ! cc0_live;
+#endif
+
+ if (GET_CODE (r) == MEM && last_mem_set && ! MEM_VOLATILE_P (r)
+ && rtx_equal_p (r, last_mem_set))
+ return 1;
- REG_N_REFS (regno) += loop_depth;
-
- /* The insns where a reg is live are normally counted
- elsewhere, but we want the count to include the insn
- where the reg is set, and the normal counting mechanism
- would not count it. */
- REG_LIVE_LENGTH (regno)++;
- }
+ while (GET_CODE (r) == SUBREG || GET_CODE (r) == STRICT_LOW_PART
+ || GET_CODE (r) == ZERO_EXTRACT)
+ r = SUBREG_REG (r);
- if (! some_not_needed)
- {
- /* Make a logical link from the next following insn
- that uses this register, back to this insn.
- The following insns have already been processed.
+ if (GET_CODE (r) == REG)
+ {
+ int regno = REGNO (r);
- We don't build a LOG_LINK for hard registers containing
- in ASM_OPERANDs. If these registers get replaced,
- we might wind up changing the semantics of the insn,
- even if reload can make what appear to be valid assignments
- later. */
- if (y && (BLOCK_NUM (y) == blocknum)
- && (regno >= FIRST_PSEUDO_REGISTER
- || asm_noperands (PATTERN (y)) < 0))
- LOG_LINKS (y)
- = gen_rtx (INSN_LIST, VOIDmode, insn, LOG_LINKS (y));
- }
- else if (! some_needed)
- {
- /* Note that dead stores have already been deleted when possible
- If we get here, we have found a dead store that cannot
- be eliminated (because the same insn does something useful).
- Indicate this by marking the reg being set as dying here. */
- REG_NOTES (insn)
- = gen_rtx (EXPR_LIST, REG_UNUSED, reg, REG_NOTES (insn));
- REG_N_DEATHS (REGNO (reg))++;
- }
- else
- {
- /* This is a case where we have a multi-word hard register
- and some, but not all, of the words of the register are
- needed in subsequent insns. Write REG_UNUSED notes
- for those parts that were not needed. This case should
- be rare. */
+ /* Don't delete insns to set global regs. */
+ if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
+ /* Make sure insns to set frame pointer aren't deleted. */
+ || regno == FRAME_POINTER_REGNUM
+#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
+ || regno == HARD_FRAME_POINTER_REGNUM
+#endif
+#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
+ /* Make sure insns to set arg pointer are never deleted
+ (if the arg pointer isn't fixed, there will be a USE for
+ it, so we can treat it normally). */
+ || (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
+#endif
+ || REGNO_REG_SET_P (needed, regno))
+ return 0;
- int i;
+ /* If this is a hard register, verify that subsequent words are
+ not needed. */
+ if (regno < FIRST_PSEUDO_REGISTER)
+ {
+ int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
- for (i = HARD_REGNO_NREGS (regno, GET_MODE (reg)) - 1;
- i >= 0; i--)
- if (!REGNO_REG_SET_P (needed, regno + i))
- REG_NOTES (insn)
- = gen_rtx (EXPR_LIST, REG_UNUSED,
- gen_rtx (REG, reg_raw_mode[regno + i],
- regno + i),
- REG_NOTES (insn));
+ while (--n > 0)
+ if (REGNO_REG_SET_P (needed, regno+n))
+ return 0;
}
+
+ return 1;
}
}
- else if (GET_CODE (reg) == REG)
- reg_next_use[regno] = 0;
- /* If this is the last pass and this is a SCRATCH, show it will be dying
- here and count it. */
- else if (GET_CODE (reg) == SCRATCH && insn != 0)
+ /* If performing several activities,
+ insn is dead if each activity is individually dead.
+ Also, CLOBBERs and USEs can be ignored; a CLOBBER or USE
+ that's inside a PARALLEL doesn't make the insn worth keeping. */
+ else if (code == PARALLEL)
{
- REG_NOTES (insn)
- = gen_rtx (EXPR_LIST, REG_UNUSED, reg, REG_NOTES (insn));
- num_scratch++;
+ int i = XVECLEN (x, 0);
+
+ for (i--; i >= 0; i--)
+ if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
+ && GET_CODE (XVECEXP (x, 0, i)) != USE
+ && ! insn_dead_p (XVECEXP (x, 0, i), needed, call_ok))
+ return 0;
+
+ return 1;
}
+
+ /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
+ is not necessarily true for hard registers. */
+ else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
+ && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
+ && ! REGNO_REG_SET_P (needed, REGNO (XEXP (x, 0))))
+ return 1;
+
+ /* We do not check other CLOBBER or USE here. An insn consisting of just
+ a CLOBBER or just a USE should not be deleted. */
+ return 0;
}
-\f
-#ifdef AUTO_INC_DEC
-/* X is a MEM found in INSN. See if we can convert it into an auto-increment
- reference. */
+/* If X is the pattern of the last insn in a libcall, and assuming X is dead,
+ return 1 if the entire library call is dead.
+ This is true if X copies a register (hard or pseudo)
+ and if the hard return reg of the call insn is dead.
+ (The caller should have tested the destination of X already for death.)
-static void
-find_auto_inc (needed, x, insn)
- regset needed;
+ If this insn doesn't just copy a register, then we don't
+ have an ordinary libcall. In that case, cse could not have
+ managed to substitute the source for the dest later on,
+ so we can assume the libcall is dead.
+
+ NEEDED is the bit vector of pseudoregs live before this insn.
+ NOTE is the REG_RETVAL note of the insn. INSN is the insn itself. */
+
+static int
+libcall_dead_p (x, needed, note, insn)
rtx x;
+ regset needed;
+ rtx note;
rtx insn;
{
- rtx addr = XEXP (x, 0);
- HOST_WIDE_INT offset = 0;
- rtx set;
-
- /* Here we detect use of an index register which might be good for
- postincrement, postdecrement, preincrement, or predecrement. */
-
- if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
- offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
+ register RTX_CODE code = GET_CODE (x);
- if (GET_CODE (addr) == REG)
+ if (code == SET)
{
- register rtx y;
- register int size = GET_MODE_SIZE (GET_MODE (x));
- rtx use;
- rtx incr;
- int regno = REGNO (addr);
+ register rtx r = SET_SRC (x);
+ if (GET_CODE (r) == REG)
+ {
+ rtx call = XEXP (note, 0);
+ register int i;
+
+ /* Find the call insn. */
+ while (call != insn && GET_CODE (call) != CALL_INSN)
+ call = NEXT_INSN (call);
+
+ /* If there is none, do nothing special,
+ since ordinary death handling can understand these insns. */
+ if (call == insn)
+ return 0;
+
+ /* See if the hard reg holding the value is dead.
+ If this is a PARALLEL, find the call within it. */
+ call = PATTERN (call);
+ if (GET_CODE (call) == PARALLEL)
+ {
+ for (i = XVECLEN (call, 0) - 1; i >= 0; i--)
+ if (GET_CODE (XVECEXP (call, 0, i)) == SET
+ && GET_CODE (SET_SRC (XVECEXP (call, 0, i))) == CALL)
+ break;
+
+ /* This may be a library call that is returning a value
+ via invisible pointer. Do nothing special, since
+ ordinary death handling can understand these insns. */
+ if (i < 0)
+ return 0;
+
+ call = XVECEXP (call, 0, i);
+ }
+
+ return insn_dead_p (call, needed, 1);
+ }
+ }
+ return 1;
+}
+
+/* Return 1 if register REGNO was used before it was set, i.e. if it is
+ live at function entry. Don't count global register variables, variables
+ in registers that can be used for function arg passing, or variables in
+ fixed hard registers. */
+
+int
+regno_uninitialized (regno)
+ int regno;
+{
+ if (n_basic_blocks == 0
+ || (regno < FIRST_PSEUDO_REGISTER
+ && (global_regs[regno]
+ || fixed_regs[regno]
+ || FUNCTION_ARG_REGNO_P (regno))))
+ return 0;
+
+ return REGNO_REG_SET_P (basic_block_live_at_start[0], regno);
+}
+
+/* 1 if register REGNO was alive at a place where `setjmp' was called
+ and was set more than once or is an argument.
+ Such regs may be clobbered by `longjmp'. */
+
+int
+regno_clobbered_at_setjmp (regno)
+ int regno;
+{
+ if (n_basic_blocks == 0)
+ return 0;
+
+ return ((REG_N_SETS (regno) > 1
+ || REGNO_REG_SET_P (basic_block_live_at_start[0], regno))
+ && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
+}
+\f
+/* Process the registers that are set within X.
+ Their bits are set to 1 in the regset DEAD,
+ because they are dead prior to this insn.
+
+ If INSN is nonzero, it is the insn being processed
+ and the fact that it is nonzero implies this is the FINAL pass
+ in propagate_block. In this case, various info about register
+ usage is stored, LOG_LINKS fields of insns are set up. */
+
+static void
+mark_set_regs (needed, dead, x, insn, significant)
+ regset needed;
+ regset dead;
+ rtx x;
+ rtx insn;
+ regset significant;
+{
+ register RTX_CODE code = GET_CODE (x);
+
+ if (code == SET || code == CLOBBER)
+ mark_set_1 (needed, dead, x, insn, significant);
+ else if (code == PARALLEL)
+ {
+ register int i;
+ for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
+ {
+ code = GET_CODE (XVECEXP (x, 0, i));
+ if (code == SET || code == CLOBBER)
+ mark_set_1 (needed, dead, XVECEXP (x, 0, i), insn, significant);
+ }
+ }
+}
+
+/* Process a single SET rtx, X. */
+
+static void
+mark_set_1 (needed, dead, x, insn, significant)
+ regset needed;
+ regset dead;
+ rtx x;
+ rtx insn;
+ regset significant;
+{
+ register int regno;
+ register rtx reg = SET_DEST (x);
+
+ /* Some targets place small structures in registers for
+ return values of functions. We have to detect this
+ case specially here to get correct flow information. */
+ if (GET_CODE (reg) == PARALLEL
+ && GET_MODE (reg) == BLKmode)
+ {
+ register int i;
+
+ for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
+ mark_set_1 (needed, dead, XVECEXP (reg, 0, i), insn, significant);
+ return;
+ }
+
+ /* Modifying just one hardware register of a multi-reg value
+ or just a byte field of a register
+ does not mean the value from before this insn is now dead.
+ But it does mean liveness of that register at the end of the block
+ is significant.
+
+ Within mark_set_1, however, we treat it as if the register is
+ indeed modified. mark_used_regs will, however, also treat this
+ register as being used. Thus, we treat these insns as setting a
+ new value for the register as a function of its old value. This
+ cases LOG_LINKS to be made appropriately and this will help combine. */
+
+ while (GET_CODE (reg) == SUBREG || GET_CODE (reg) == ZERO_EXTRACT
+ || GET_CODE (reg) == SIGN_EXTRACT
+ || GET_CODE (reg) == STRICT_LOW_PART)
+ reg = XEXP (reg, 0);
+
+ /* If we are writing into memory or into a register mentioned in the
+ address of the last thing stored into memory, show we don't know
+ what the last store was. If we are writing memory, save the address
+ unless it is volatile. */
+ if (GET_CODE (reg) == MEM
+ || (GET_CODE (reg) == REG
+ && last_mem_set != 0 && reg_overlap_mentioned_p (reg, last_mem_set)))
+ last_mem_set = 0;
+
+ if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
+ /* There are no REG_INC notes for SP, so we can't assume we'll see
+ everything that invalidates it. To be safe, don't eliminate any
+ stores though SP; none of them should be redundant anyway. */
+ && ! reg_mentioned_p (stack_pointer_rtx, reg))
+ last_mem_set = reg;
+
+ if (GET_CODE (reg) == REG
+ && (regno = REGNO (reg), regno != FRAME_POINTER_REGNUM)
+#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
+ && regno != HARD_FRAME_POINTER_REGNUM
+#endif
+#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
+ && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
+#endif
+ && ! (regno < FIRST_PSEUDO_REGISTER && global_regs[regno]))
+ /* && regno != STACK_POINTER_REGNUM) -- let's try without this. */
+ {
+ int some_needed = REGNO_REG_SET_P (needed, regno);
+ int some_not_needed = ! some_needed;
+
+ /* Mark it as a significant register for this basic block. */
+ if (significant)
+ SET_REGNO_REG_SET (significant, regno);
+
+ /* Mark it as dead before this insn. */
+ SET_REGNO_REG_SET (dead, regno);
+
+ /* A hard reg in a wide mode may really be multiple registers.
+ If so, mark all of them just like the first. */
+ if (regno < FIRST_PSEUDO_REGISTER)
+ {
+ int n;
+
+ /* Nothing below is needed for the stack pointer; get out asap.
+ Eg, log links aren't needed, since combine won't use them. */
+ if (regno == STACK_POINTER_REGNUM)
+ return;
+
+ n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
+ while (--n > 0)
+ {
+ int regno_n = regno + n;
+ int needed_regno = REGNO_REG_SET_P (needed, regno_n);
+ if (significant)
+ SET_REGNO_REG_SET (significant, regno_n);
+
+ SET_REGNO_REG_SET (dead, regno_n);
+ some_needed |= needed_regno;
+ some_not_needed |= ! needed_regno;
+ }
+ }
+ /* Additional data to record if this is the final pass. */
+ if (insn)
+ {
+ register rtx y = reg_next_use[regno];
+ register int blocknum = BLOCK_NUM (insn);
+
+ /* If this is a hard reg, record this function uses the reg. */
+
+ if (regno < FIRST_PSEUDO_REGISTER)
+ {
+ register int i;
+ int endregno = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg));
+
+ for (i = regno; i < endregno; i++)
+ {
+ /* The next use is no longer "next", since a store
+ intervenes. */
+ reg_next_use[i] = 0;
+
+ regs_ever_live[i] = 1;
+ REG_N_SETS (i)++;
+ }
+ }
+ else
+ {
+ /* The next use is no longer "next", since a store
+ intervenes. */
+ reg_next_use[regno] = 0;
+
+ /* Keep track of which basic blocks each reg appears in. */
+
+ if (REG_BASIC_BLOCK (regno) == REG_BLOCK_UNKNOWN)
+ REG_BASIC_BLOCK (regno) = blocknum;
+ else if (REG_BASIC_BLOCK (regno) != blocknum)
+ REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL;
+
+ /* Count (weighted) references, stores, etc. This counts a
+ register twice if it is modified, but that is correct. */
+ REG_N_SETS (regno)++;
+
+ REG_N_REFS (regno) += loop_depth;
+
+ /* The insns where a reg is live are normally counted
+ elsewhere, but we want the count to include the insn
+ where the reg is set, and the normal counting mechanism
+ would not count it. */
+ REG_LIVE_LENGTH (regno)++;
+ }
+
+ if (! some_not_needed)
+ {
+ /* Make a logical link from the next following insn
+ that uses this register, back to this insn.
+ The following insns have already been processed.
+
+ We don't build a LOG_LINK for hard registers containing
+ in ASM_OPERANDs. If these registers get replaced,
+ we might wind up changing the semantics of the insn,
+ even if reload can make what appear to be valid assignments
+ later. */
+ if (y && (BLOCK_NUM (y) == blocknum)
+ && (regno >= FIRST_PSEUDO_REGISTER
+ || asm_noperands (PATTERN (y)) < 0))
+ LOG_LINKS (y)
+ = gen_rtx_INSN_LIST (VOIDmode, insn, LOG_LINKS (y));
+ }
+ else if (! some_needed)
+ {
+ /* Note that dead stores have already been deleted when possible
+ If we get here, we have found a dead store that cannot
+ be eliminated (because the same insn does something useful).
+ Indicate this by marking the reg being set as dying here. */
+ REG_NOTES (insn)
+ = gen_rtx_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
+ REG_N_DEATHS (REGNO (reg))++;
+ }
+ else
+ {
+ /* This is a case where we have a multi-word hard register
+ and some, but not all, of the words of the register are
+ needed in subsequent insns. Write REG_UNUSED notes
+ for those parts that were not needed. This case should
+ be rare. */
+
+ int i;
+
+ for (i = HARD_REGNO_NREGS (regno, GET_MODE (reg)) - 1;
+ i >= 0; i--)
+ if (!REGNO_REG_SET_P (needed, regno + i))
+ REG_NOTES (insn)
+ = gen_rtx_EXPR_LIST (REG_UNUSED,
+ gen_rtx_REG (reg_raw_mode[regno + i],
+ regno + i),
+ REG_NOTES (insn));
+ }
+ }
+ }
+ else if (GET_CODE (reg) == REG)
+ reg_next_use[regno] = 0;
+
+ /* If this is the last pass and this is a SCRATCH, show it will be dying
+ here and count it. */
+ else if (GET_CODE (reg) == SCRATCH && insn != 0)
+ {
+ REG_NOTES (insn)
+ = gen_rtx_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
+ }
+}
+\f
+#ifdef AUTO_INC_DEC
+
+/* X is a MEM found in INSN. See if we can convert it into an auto-increment
+ reference. */
+
+static void
+find_auto_inc (needed, x, insn)
+ regset needed;
+ rtx x;
+ rtx insn;
+{
+ rtx addr = XEXP (x, 0);
+ HOST_WIDE_INT offset = 0;
+ rtx set;
+
+ /* Here we detect use of an index register which might be good for
+ postincrement, postdecrement, preincrement, or predecrement. */
+
+ if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
+ offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
+
+ if (GET_CODE (addr) == REG)
+ {
+ register rtx y;
+ register int size = GET_MODE_SIZE (GET_MODE (x));
+ rtx use;
+ rtx incr;
+ int regno = REGNO (addr);
+
+ /* Is the next use an increment that might make auto-increment? */
+ if ((incr = reg_next_use[regno]) != 0
+ && (set = single_set (incr)) != 0
+ && GET_CODE (set) == SET
+ && BLOCK_NUM (incr) == BLOCK_NUM (insn)
+ /* Can't add side effects to jumps; if reg is spilled and
+ reloaded, there's no way to store back the altered value. */
+ && GET_CODE (insn) != JUMP_INSN
+ && (y = SET_SRC (set), GET_CODE (y) == PLUS)
+ && XEXP (y, 0) == addr
+ && GET_CODE (XEXP (y, 1)) == CONST_INT
+ && (0
+#ifdef HAVE_POST_INCREMENT
+ || (INTVAL (XEXP (y, 1)) == size && offset == 0)
+#endif
+#ifdef HAVE_POST_DECREMENT
+ || (INTVAL (XEXP (y, 1)) == - size && offset == 0)
+#endif
+#ifdef HAVE_PRE_INCREMENT
+ || (INTVAL (XEXP (y, 1)) == size && offset == size)
+#endif
+#ifdef HAVE_PRE_DECREMENT
+ || (INTVAL (XEXP (y, 1)) == - size && offset == - size)
+#endif
+ )
+ /* Make sure this reg appears only once in this insn. */
+ && (use = find_use_as_address (PATTERN (insn), addr, offset),
+ use != 0 && use != (rtx) 1))
+ {
+ rtx q = SET_DEST (set);
+ enum rtx_code inc_code = (INTVAL (XEXP (y, 1)) == size
+ ? (offset ? PRE_INC : POST_INC)
+ : (offset ? PRE_DEC : POST_DEC));
+
+ if (dead_or_set_p (incr, addr))
+ {
+ /* This is the simple case. Try to make the auto-inc. If
+ we can't, we are done. Otherwise, we will do any
+ needed updates below. */
+ if (! validate_change (insn, &XEXP (x, 0),
+ gen_rtx_fmt_e (inc_code, Pmode, addr),
+ 0))
+ return;
+ }
+ else if (GET_CODE (q) == REG
+ /* PREV_INSN used here to check the semi-open interval
+ [insn,incr). */
+ && ! reg_used_between_p (q, PREV_INSN (insn), incr)
+ /* We must also check for sets of q as q may be
+ a call clobbered hard register and there may
+ be a call between PREV_INSN (insn) and incr. */
+ && ! reg_set_between_p (q, PREV_INSN (insn), incr))
+ {
+ /* We have *p followed sometime later by q = p+size.
+ Both p and q must be live afterward,
+ and q is not used between INSN and its assignment.
+ Change it to q = p, ...*q..., q = q+size.
+ Then fall into the usual case. */
+ rtx insns, temp;
+
+ start_sequence ();
+ emit_move_insn (q, addr);
+ insns = get_insns ();
+ end_sequence ();
+
+ /* If anything in INSNS have UID's that don't fit within the
+ extra space we allocate earlier, we can't make this auto-inc.
+ This should never happen. */
+ for (temp = insns; temp; temp = NEXT_INSN (temp))
+ {
+ if (INSN_UID (temp) > max_uid_for_flow)
+ return;
+ BLOCK_NUM (temp) = BLOCK_NUM (insn);
+ }
+
+ /* If we can't make the auto-inc, or can't make the
+ replacement into Y, exit. There's no point in making
+ the change below if we can't do the auto-inc and doing
+ so is not correct in the pre-inc case. */
+
+ validate_change (insn, &XEXP (x, 0),
+ gen_rtx_fmt_e (inc_code, Pmode, q),
+ 1);
+ validate_change (incr, &XEXP (y, 0), q, 1);
+ if (! apply_change_group ())
+ return;
+
+ /* We now know we'll be doing this change, so emit the
+ new insn(s) and do the updates. */
+ emit_insns_before (insns, insn);
+
+ if (basic_block_head[BLOCK_NUM (insn)] == insn)
+ basic_block_head[BLOCK_NUM (insn)] = insns;
+
+ /* INCR will become a NOTE and INSN won't contain a
+ use of ADDR. If a use of ADDR was just placed in
+ the insn before INSN, make that the next use.
+ Otherwise, invalidate it. */
+ if (GET_CODE (PREV_INSN (insn)) == INSN
+ && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
+ && SET_SRC (PATTERN (PREV_INSN (insn))) == addr)
+ reg_next_use[regno] = PREV_INSN (insn);
+ else
+ reg_next_use[regno] = 0;
+
+ addr = q;
+ regno = REGNO (q);
+
+ /* REGNO is now used in INCR which is below INSN, but
+ it previously wasn't live here. If we don't mark
+ it as needed, we'll put a REG_DEAD note for it
+ on this insn, which is incorrect. */
+ SET_REGNO_REG_SET (needed, regno);
+
+ /* If there are any calls between INSN and INCR, show
+ that REGNO now crosses them. */
+ for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
+ if (GET_CODE (temp) == CALL_INSN)
+ REG_N_CALLS_CROSSED (regno)++;
+ }
+ else
+ return;
+
+ /* If we haven't returned, it means we were able to make the
+ auto-inc, so update the status. First, record that this insn
+ has an implicit side effect. */
+
+ REG_NOTES (insn)
+ = gen_rtx_EXPR_LIST (REG_INC, addr, REG_NOTES (insn));
+
+ /* Modify the old increment-insn to simply copy
+ the already-incremented value of our register. */
+ if (! validate_change (incr, &SET_SRC (set), addr, 0))
+ abort ();
+
+ /* If that makes it a no-op (copying the register into itself) delete
+ it so it won't appear to be a "use" and a "set" of this
+ register. */
+ if (SET_DEST (set) == addr)
+ {
+ PUT_CODE (incr, NOTE);
+ NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
+ NOTE_SOURCE_FILE (incr) = 0;
+ }
+
+ if (regno >= FIRST_PSEUDO_REGISTER)
+ {
+ /* Count an extra reference to the reg. When a reg is
+ incremented, spilling it is worse, so we want to make
+ that less likely. */
+ REG_N_REFS (regno) += loop_depth;
+
+ /* Count the increment as a setting of the register,
+ even though it isn't a SET in rtl. */
+ REG_N_SETS (regno)++;
+ }
+ }
+ }
+}
+#endif /* AUTO_INC_DEC */
+\f
+/* Scan expression X and store a 1-bit in LIVE for each reg it uses.
+ This is done assuming the registers needed from X
+ are those that have 1-bits in NEEDED.
+
+ On the final pass, FINAL is 1. This means try for autoincrement
+ and count the uses and deaths of each pseudo-reg.
+
+ INSN is the containing instruction. If INSN is dead, this function is not
+ called. */
+
+static void
+mark_used_regs (needed, live, x, final, insn)
+ regset needed;
+ regset live;
+ rtx x;
+ int final;
+ rtx insn;
+{
+ register RTX_CODE code;
+ register int regno;
+ int i;
+
+ retry:
+ code = GET_CODE (x);
+ switch (code)
+ {
+ case LABEL_REF:
+ case SYMBOL_REF:
+ case CONST_INT:
+ case CONST:
+ case CONST_DOUBLE:
+ case PC:
+ case ADDR_VEC:
+ case ADDR_DIFF_VEC:
+ case ASM_INPUT:
+ return;
+
+#ifdef HAVE_cc0
+ case CC0:
+ cc0_live = 1;
+ return;
+#endif
+
+ case CLOBBER:
+ /* If we are clobbering a MEM, mark any registers inside the address
+ as being used. */
+ if (GET_CODE (XEXP (x, 0)) == MEM)
+ mark_used_regs (needed, live, XEXP (XEXP (x, 0), 0), final, insn);
+ return;
+
+ case MEM:
+ /* Invalidate the data for the last MEM stored, but only if MEM is
+ something that can be stored into. */
+ if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
+ && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
+ ; /* needn't clear last_mem_set */
+ else
+ last_mem_set = 0;
+
+#ifdef AUTO_INC_DEC
+ if (final)
+ find_auto_inc (needed, x, insn);
+#endif
+ break;
+
+ case SUBREG:
+ if (GET_CODE (SUBREG_REG (x)) == REG
+ && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
+ && (GET_MODE_SIZE (GET_MODE (x))
+ != GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)))))
+ REG_CHANGES_SIZE (REGNO (SUBREG_REG (x))) = 1;
+
+ /* While we're here, optimize this case. */
+ x = SUBREG_REG (x);
+
+ /* In case the SUBREG is not of a register, don't optimize */
+ if (GET_CODE (x) != REG)
+ {
+ mark_used_regs (needed, live, x, final, insn);
+ return;
+ }
+
+ /* ... fall through ... */
+
+ case REG:
+ /* See a register other than being set
+ => mark it as needed. */
+
+ regno = REGNO (x);
+ {
+ int some_needed = REGNO_REG_SET_P (needed, regno);
+ int some_not_needed = ! some_needed;
+
+ SET_REGNO_REG_SET (live, regno);
+
+ /* A hard reg in a wide mode may really be multiple registers.
+ If so, mark all of them just like the first. */
+ if (regno < FIRST_PSEUDO_REGISTER)
+ {
+ int n;
+
+ /* For stack ptr or fixed arg pointer,
+ nothing below can be necessary, so waste no more time. */
+ if (regno == STACK_POINTER_REGNUM
+#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
+ || regno == HARD_FRAME_POINTER_REGNUM
+#endif
+#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
+ || (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
+#endif
+ || regno == FRAME_POINTER_REGNUM)
+ {
+ /* If this is a register we are going to try to eliminate,
+ don't mark it live here. If we are successful in
+ eliminating it, it need not be live unless it is used for
+ pseudos, in which case it will have been set live when
+ it was allocated to the pseudos. If the register will not
+ be eliminated, reload will set it live at that point. */
+
+ if (! TEST_HARD_REG_BIT (elim_reg_set, regno))
+ regs_ever_live[regno] = 1;
+ return;
+ }
+ /* No death notes for global register variables;
+ their values are live after this function exits. */
+ if (global_regs[regno])
+ {
+ if (final)
+ reg_next_use[regno] = insn;
+ return;
+ }
+
+ n = HARD_REGNO_NREGS (regno, GET_MODE (x));
+ while (--n > 0)
+ {
+ int regno_n = regno + n;
+ int needed_regno = REGNO_REG_SET_P (needed, regno_n);
+
+ SET_REGNO_REG_SET (live, regno_n);
+ some_needed |= needed_regno;
+ some_not_needed |= ! needed_regno;
+ }
+ }
+ if (final)
+ {
+ /* Record where each reg is used, so when the reg
+ is set we know the next insn that uses it. */
+
+ reg_next_use[regno] = insn;
+
+ if (regno < FIRST_PSEUDO_REGISTER)
+ {
+ /* If a hard reg is being used,
+ record that this function does use it. */
+
+ i = HARD_REGNO_NREGS (regno, GET_MODE (x));
+ if (i == 0)
+ i = 1;
+ do
+ regs_ever_live[regno + --i] = 1;
+ while (i > 0);
+ }
+ else
+ {
+ /* Keep track of which basic block each reg appears in. */
+
+ register int blocknum = BLOCK_NUM (insn);
+
+ if (REG_BASIC_BLOCK (regno) == REG_BLOCK_UNKNOWN)
+ REG_BASIC_BLOCK (regno) = blocknum;
+ else if (REG_BASIC_BLOCK (regno) != blocknum)
+ REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL;
+
+ /* Count (weighted) number of uses of each reg. */
+
+ REG_N_REFS (regno) += loop_depth;
+ }
+
+ /* Record and count the insns in which a reg dies.
+ If it is used in this insn and was dead below the insn
+ then it dies in this insn. If it was set in this insn,
+ we do not make a REG_DEAD note; likewise if we already
+ made such a note. */
+
+ if (some_not_needed
+ && ! dead_or_set_p (insn, x)
+#if 0
+ && (regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno])
+#endif
+ )
+ {
+ /* Check for the case where the register dying partially
+ overlaps the register set by this insn. */
+ if (regno < FIRST_PSEUDO_REGISTER
+ && HARD_REGNO_NREGS (regno, GET_MODE (x)) > 1)
+ {
+ int n = HARD_REGNO_NREGS (regno, GET_MODE (x));
+ while (--n >= 0)
+ some_needed |= dead_or_set_regno_p (insn, regno + n);
+ }
+
+ /* If none of the words in X is needed, make a REG_DEAD
+ note. Otherwise, we must make partial REG_DEAD notes. */
+ if (! some_needed)
+ {
+ REG_NOTES (insn)
+ = gen_rtx_EXPR_LIST (REG_DEAD, x, REG_NOTES (insn));
+ REG_N_DEATHS (regno)++;
+ }
+ else
+ {
+ int i;
+
+ /* Don't make a REG_DEAD note for a part of a register
+ that is set in the insn. */
+
+ for (i = HARD_REGNO_NREGS (regno, GET_MODE (x)) - 1;
+ i >= 0; i--)
+ if (!REGNO_REG_SET_P (needed, regno + i)
+ && ! dead_or_set_regno_p (insn, regno + i))
+ REG_NOTES (insn)
+ = gen_rtx_EXPR_LIST (REG_DEAD,
+ gen_rtx_REG (reg_raw_mode[regno + i],
+ regno + i),
+ REG_NOTES (insn));
+ }
+ }
+ }
+ }
+ return;
+
+ case SET:
+ {
+ register rtx testreg = SET_DEST (x);
+ int mark_dest = 0;
+
+ /* If storing into MEM, don't show it as being used. But do
+ show the address as being used. */
+ if (GET_CODE (testreg) == MEM)
+ {
+#ifdef AUTO_INC_DEC
+ if (final)
+ find_auto_inc (needed, testreg, insn);
+#endif
+ mark_used_regs (needed, live, XEXP (testreg, 0), final, insn);
+ mark_used_regs (needed, live, SET_SRC (x), final, insn);
+ return;
+ }
+
+ /* Storing in STRICT_LOW_PART is like storing in a reg
+ in that this SET might be dead, so ignore it in TESTREG.
+ but in some other ways it is like using the reg.
+
+ Storing in a SUBREG or a bit field is like storing the entire
+ register in that if the register's value is not used
+ then this SET is not needed. */
+ while (GET_CODE (testreg) == STRICT_LOW_PART
+ || GET_CODE (testreg) == ZERO_EXTRACT
+ || GET_CODE (testreg) == SIGN_EXTRACT
+ || GET_CODE (testreg) == SUBREG)
+ {
+ if (GET_CODE (testreg) == SUBREG
+ && GET_CODE (SUBREG_REG (testreg)) == REG
+ && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
+ && (GET_MODE_SIZE (GET_MODE (testreg))
+ != GET_MODE_SIZE (GET_MODE (SUBREG_REG (testreg)))))
+ REG_CHANGES_SIZE (REGNO (SUBREG_REG (testreg))) = 1;
+
+ /* Modifying a single register in an alternate mode
+ does not use any of the old value. But these other
+ ways of storing in a register do use the old value. */
+ if (GET_CODE (testreg) == SUBREG
+ && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
+ ;
+ else
+ mark_dest = 1;
+
+ testreg = XEXP (testreg, 0);
+ }
+
+ /* If this is a store into a register,
+ recursively scan the value being stored. */
+
+ if ((GET_CODE (testreg) == PARALLEL
+ && GET_MODE (testreg) == BLKmode)
+ || (GET_CODE (testreg) == REG
+ && (regno = REGNO (testreg), regno != FRAME_POINTER_REGNUM)
+#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
+ && regno != HARD_FRAME_POINTER_REGNUM
+#endif
+#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
+ && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
+#endif
+ ))
+ /* We used to exclude global_regs here, but that seems wrong.
+ Storing in them is like storing in mem. */
+ {
+ mark_used_regs (needed, live, SET_SRC (x), final, insn);
+ if (mark_dest)
+ mark_used_regs (needed, live, SET_DEST (x), final, insn);
+ return;
+ }
+ }
+ break;
+
+ case RETURN:
+ /* If exiting needs the right stack value, consider this insn as
+ using the stack pointer. In any event, consider it as using
+ all global registers and all registers used by return. */
+
+#ifdef EXIT_IGNORE_STACK
+ if (! EXIT_IGNORE_STACK
+ || (! FRAME_POINTER_REQUIRED
+ && ! current_function_calls_alloca
+ && flag_omit_frame_pointer)
+ || current_function_sp_is_unchanging)
+#endif
+ SET_REGNO_REG_SET (live, STACK_POINTER_REGNUM);
+
+ for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+ if (global_regs[i]
+#ifdef EPILOGUE_USES
+ || EPILOGUE_USES (i)
+#endif
+ )
+ SET_REGNO_REG_SET (live, i);
+ break;
+
+ default:
+ break;
+ }
+
+ /* Recursively scan the operands of this expression. */
+
+ {
+ register char *fmt = GET_RTX_FORMAT (code);
+ register int i;
+
+ for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+ {
+ if (fmt[i] == 'e')
+ {
+ /* Tail recursive case: save a function call level. */
+ if (i == 0)
+ {
+ x = XEXP (x, 0);
+ goto retry;
+ }
+ mark_used_regs (needed, live, XEXP (x, i), final, insn);
+ }
+ else if (fmt[i] == 'E')
+ {
+ register int j;
+ for (j = 0; j < XVECLEN (x, i); j++)
+ mark_used_regs (needed, live, XVECEXP (x, i, j), final, insn);
+ }
+ }
+ }
+}
+\f
+#ifdef AUTO_INC_DEC
+
+static int
+try_pre_increment_1 (insn)
+ rtx insn;
+{
+ /* Find the next use of this reg. If in same basic block,
+ make it do pre-increment or pre-decrement if appropriate. */
+ rtx x = single_set (insn);
+ HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
+ * INTVAL (XEXP (SET_SRC (x), 1)));
+ int regno = REGNO (SET_DEST (x));
+ rtx y = reg_next_use[regno];
+ if (y != 0
+ && BLOCK_NUM (y) == BLOCK_NUM (insn)
+ /* Don't do this if the reg dies, or gets set in y; a standard addressing
+ mode would be better. */
+ && ! dead_or_set_p (y, SET_DEST (x))
+ && try_pre_increment (y, SET_DEST (x), amount))
+ {
+ /* We have found a suitable auto-increment
+ and already changed insn Y to do it.
+ So flush this increment-instruction. */
+ PUT_CODE (insn, NOTE);
+ NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
+ NOTE_SOURCE_FILE (insn) = 0;
+ /* Count a reference to this reg for the increment
+ insn we are deleting. When a reg is incremented.
+ spilling it is worse, so we want to make that
+ less likely. */
+ if (regno >= FIRST_PSEUDO_REGISTER)
+ {
+ REG_N_REFS (regno) += loop_depth;
+ REG_N_SETS (regno)++;
+ }
+ return 1;
+ }
+ return 0;
+}
- /* Is the next use an increment that might make auto-increment? */
- if ((incr = reg_next_use[regno]) != 0
- && (set = single_set (incr)) != 0
- && GET_CODE (set) == SET
- && BLOCK_NUM (incr) == BLOCK_NUM (insn)
- /* Can't add side effects to jumps; if reg is spilled and
- reloaded, there's no way to store back the altered value. */
- && GET_CODE (insn) != JUMP_INSN
- && (y = SET_SRC (set), GET_CODE (y) == PLUS)
- && XEXP (y, 0) == addr
- && GET_CODE (XEXP (y, 1)) == CONST_INT
- && (0
-#ifdef HAVE_POST_INCREMENT
- || (INTVAL (XEXP (y, 1)) == size && offset == 0)
-#endif
-#ifdef HAVE_POST_DECREMENT
- || (INTVAL (XEXP (y, 1)) == - size && offset == 0)
-#endif
+/* Try to change INSN so that it does pre-increment or pre-decrement
+ addressing on register REG in order to add AMOUNT to REG.
+ AMOUNT is negative for pre-decrement.
+ Returns 1 if the change could be made.
+ This checks all about the validity of the result of modifying INSN. */
+
+static int
+try_pre_increment (insn, reg, amount)
+ rtx insn, reg;
+ HOST_WIDE_INT amount;
+{
+ register rtx use;
+
+ /* Nonzero if we can try to make a pre-increment or pre-decrement.
+ For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
+ int pre_ok = 0;
+ /* Nonzero if we can try to make a post-increment or post-decrement.
+ For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
+ It is possible for both PRE_OK and POST_OK to be nonzero if the machine
+ supports both pre-inc and post-inc, or both pre-dec and post-dec. */
+ int post_ok = 0;
+
+ /* Nonzero if the opportunity actually requires post-inc or post-dec. */
+ int do_post = 0;
+
+ /* From the sign of increment, see which possibilities are conceivable
+ on this target machine. */
#ifdef HAVE_PRE_INCREMENT
- || (INTVAL (XEXP (y, 1)) == size && offset == size)
+ if (amount > 0)
+ pre_ok = 1;
#endif
+#ifdef HAVE_POST_INCREMENT
+ if (amount > 0)
+ post_ok = 1;
+#endif
+
#ifdef HAVE_PRE_DECREMENT
- || (INTVAL (XEXP (y, 1)) == - size && offset == - size)
+ if (amount < 0)
+ pre_ok = 1;
#endif
- )
- /* Make sure this reg appears only once in this insn. */
- && (use = find_use_as_address (PATTERN (insn), addr, offset),
- use != 0 && use != (rtx) 1))
+#ifdef HAVE_POST_DECREMENT
+ if (amount < 0)
+ post_ok = 1;
+#endif
+
+ if (! (pre_ok || post_ok))
+ return 0;
+
+ /* It is not safe to add a side effect to a jump insn
+ because if the incremented register is spilled and must be reloaded
+ there would be no way to store the incremented value back in memory. */
+
+ if (GET_CODE (insn) == JUMP_INSN)
+ return 0;
+
+ use = 0;
+ if (pre_ok)
+ use = find_use_as_address (PATTERN (insn), reg, 0);
+ if (post_ok && (use == 0 || use == (rtx) 1))
+ {
+ use = find_use_as_address (PATTERN (insn), reg, -amount);
+ do_post = 1;
+ }
+
+ if (use == 0 || use == (rtx) 1)
+ return 0;
+
+ if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
+ return 0;
+
+ /* See if this combination of instruction and addressing mode exists. */
+ if (! validate_change (insn, &XEXP (use, 0),
+ gen_rtx_fmt_e (amount > 0
+ ? (do_post ? POST_INC : PRE_INC)
+ : (do_post ? POST_DEC : PRE_DEC),
+ Pmode, reg), 0))
+ return 0;
+
+ /* Record that this insn now has an implicit side effect on X. */
+ REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
+ return 1;
+}
+
+#endif /* AUTO_INC_DEC */
+\f
+/* Find the place in the rtx X where REG is used as a memory address.
+ Return the MEM rtx that so uses it.
+ If PLUSCONST is nonzero, search instead for a memory address equivalent to
+ (plus REG (const_int PLUSCONST)).
+
+ If such an address does not appear, return 0.
+ If REG appears more than once, or is used other than in such an address,
+ return (rtx)1. */
+
+rtx
+find_use_as_address (x, reg, plusconst)
+ register rtx x;
+ rtx reg;
+ HOST_WIDE_INT plusconst;
+{
+ enum rtx_code code = GET_CODE (x);
+ char *fmt = GET_RTX_FORMAT (code);
+ register int i;
+ register rtx value = 0;
+ register rtx tem;
+
+ if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
+ return x;
+
+ if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
+ && XEXP (XEXP (x, 0), 0) == reg
+ && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
+ && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
+ return x;
+
+ if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
+ {
+ /* If REG occurs inside a MEM used in a bit-field reference,
+ that is unacceptable. */
+ if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
+ return (rtx) (HOST_WIDE_INT) 1;
+ }
+
+ if (x == reg)
+ return (rtx) (HOST_WIDE_INT) 1;
+
+ for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+ {
+ if (fmt[i] == 'e')
+ {
+ tem = find_use_as_address (XEXP (x, i), reg, plusconst);
+ if (value == 0)
+ value = tem;
+ else if (tem != 0)
+ return (rtx) (HOST_WIDE_INT) 1;
+ }
+ if (fmt[i] == 'E')
+ {
+ register int j;
+ for (j = XVECLEN (x, i) - 1; j >= 0; j--)
+ {
+ tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
+ if (value == 0)
+ value = tem;
+ else if (tem != 0)
+ return (rtx) (HOST_WIDE_INT) 1;
+ }
+ }
+ }
+
+ return value;
+}
+\f
+/* Write information about registers and basic blocks into FILE.
+ This is part of making a debugging dump. */
+
+void
+dump_flow_info (file)
+ FILE *file;
+{
+ register int i;
+ static char *reg_class_names[] = REG_CLASS_NAMES;
+
+ fprintf (file, "%d registers.\n", max_regno);
+
+ for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
+ if (REG_N_REFS (i))
+ {
+ enum reg_class class, altclass;
+ fprintf (file, "\nRegister %d used %d times across %d insns",
+ i, REG_N_REFS (i), REG_LIVE_LENGTH (i));
+ if (REG_BASIC_BLOCK (i) >= 0)
+ fprintf (file, " in block %d", REG_BASIC_BLOCK (i));
+ if (REG_N_SETS (i))
+ fprintf (file, "; set %d time%s", REG_N_SETS (i),
+ (REG_N_SETS (i) == 1) ? "" : "s");
+ if (REG_USERVAR_P (regno_reg_rtx[i]))
+ fprintf (file, "; user var");
+ if (REG_N_DEATHS (i) != 1)
+ fprintf (file, "; dies in %d places", REG_N_DEATHS (i));
+ if (REG_N_CALLS_CROSSED (i) == 1)
+ fprintf (file, "; crosses 1 call");
+ else if (REG_N_CALLS_CROSSED (i))
+ fprintf (file, "; crosses %d calls", REG_N_CALLS_CROSSED (i));
+ if (PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD)
+ fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i));
+ class = reg_preferred_class (i);
+ altclass = reg_alternate_class (i);
+ if (class != GENERAL_REGS || altclass != ALL_REGS)
+ {
+ if (altclass == ALL_REGS || class == ALL_REGS)
+ fprintf (file, "; pref %s", reg_class_names[(int) class]);
+ else if (altclass == NO_REGS)
+ fprintf (file, "; %s or none", reg_class_names[(int) class]);
+ else
+ fprintf (file, "; pref %s, else %s",
+ reg_class_names[(int) class],
+ reg_class_names[(int) altclass]);
+ }
+ if (REGNO_POINTER_FLAG (i))
+ fprintf (file, "; pointer");
+ fprintf (file, ".\n");
+ }
+ fprintf (file, "\n%d basic blocks.\n", n_basic_blocks);
+ dump_bb_data (file, basic_block_pred, basic_block_succ, 1);
+}
+
+\f
+/* Like print_rtl, but also print out live information for the start of each
+ basic block. */
+
+void
+print_rtl_with_bb (outf, rtx_first)
+ FILE *outf;
+ rtx rtx_first;
+{
+ register rtx tmp_rtx;
+
+ if (rtx_first == 0)
+ fprintf (outf, "(nil)\n");
+
+ else
+ {
+ int i, bb;
+ enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
+ int max_uid = get_max_uid ();
+ int *start = (int *) alloca (max_uid * sizeof (int));
+ int *end = (int *) alloca (max_uid * sizeof (int));
+ enum bb_state *in_bb_p = (enum bb_state *)
+ alloca (max_uid * sizeof (enum bb_state));
+
+ for (i = 0; i < max_uid; i++)
+ {
+ start[i] = end[i] = -1;
+ in_bb_p[i] = NOT_IN_BB;
+ }
+
+ for (i = n_basic_blocks-1; i >= 0; i--)
+ {
+ rtx x;
+ start[INSN_UID (basic_block_head[i])] = i;
+ end[INSN_UID (basic_block_end[i])] = i;
+ for (x = basic_block_head[i]; x != NULL_RTX; x = NEXT_INSN (x))
+ {
+ in_bb_p[ INSN_UID(x)]
+ = (in_bb_p[ INSN_UID(x)] == NOT_IN_BB)
+ ? IN_ONE_BB : IN_MULTIPLE_BB;
+ if (x == basic_block_end[i])
+ break;
+ }
+ }
+
+ for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
{
- rtx q = SET_DEST (set);
- enum rtx_code inc_code = (INTVAL (XEXP (y, 1)) == size
- ? (offset ? PRE_INC : POST_INC)
- : (offset ? PRE_DEC : POST_DEC));
+ int did_output;
- if (dead_or_set_p (incr, addr))
+ if ((bb = start[INSN_UID (tmp_rtx)]) >= 0)
{
- /* This is the simple case. Try to make the auto-inc. If
- we can't, we are done. Otherwise, we will do any
- needed updates below. */
- if (! validate_change (insn, &XEXP (x, 0),
- gen_rtx (inc_code, Pmode, addr),
- 0))
- return;
+ fprintf (outf, ";; Start of basic block %d, registers live:",
+ bb);
+
+ EXECUTE_IF_SET_IN_REG_SET (basic_block_live_at_start[bb], 0, i,
+ {
+ fprintf (outf, " %d", i);
+ if (i < FIRST_PSEUDO_REGISTER)
+ fprintf (outf, " [%s]",
+ reg_names[i]);
+ });
+ putc ('\n', outf);
}
- else if (GET_CODE (q) == REG
- /* PREV_INSN used here to check the semi-open interval
- [insn,incr). */
- && ! reg_used_between_p (q, PREV_INSN (insn), incr)
- /* We must also check for sets of q as q may be
- a call clobbered hard register and there may
- be a call between PREV_INSN (insn) and incr. */
- && ! reg_set_between_p (q, PREV_INSN (insn), incr))
- {
- /* We have *p followed sometime later by q = p+size.
- Both p and q must be live afterward,
- and q is not used between INSN and it's assignment.
- Change it to q = p, ...*q..., q = q+size.
- Then fall into the usual case. */
- rtx insns, temp;
- start_sequence ();
- emit_move_insn (q, addr);
- insns = get_insns ();
- end_sequence ();
+ if (in_bb_p[ INSN_UID(tmp_rtx)] == NOT_IN_BB
+ && GET_CODE (tmp_rtx) != NOTE
+ && GET_CODE (tmp_rtx) != BARRIER)
+ fprintf (outf, ";; Insn is not within a basic block\n");
+ else if (in_bb_p[ INSN_UID(tmp_rtx)] == IN_MULTIPLE_BB)
+ fprintf (outf, ";; Insn is in multiple basic blocks\n");
- /* If anything in INSNS have UID's that don't fit within the
- extra space we allocate earlier, we can't make this auto-inc.
- This should never happen. */
- for (temp = insns; temp; temp = NEXT_INSN (temp))
- {
- if (INSN_UID (temp) > max_uid_for_flow)
- return;
- BLOCK_NUM (temp) = BLOCK_NUM (insn);
- }
+ did_output = print_rtl_single (outf, tmp_rtx);
- /* If we can't make the auto-inc, or can't make the
- replacement into Y, exit. There's no point in making
- the change below if we can't do the auto-inc and doing
- so is not correct in the pre-inc case. */
+ if ((bb = end[INSN_UID (tmp_rtx)]) >= 0)
+ fprintf (outf, ";; End of basic block %d\n", bb);
- validate_change (insn, &XEXP (x, 0),
- gen_rtx (inc_code, Pmode, q),
- 1);
- validate_change (incr, &XEXP (y, 0), q, 1);
- if (! apply_change_group ())
- return;
+ if (did_output)
+ putc ('\n', outf);
+ }
+ }
+}
- /* We now know we'll be doing this change, so emit the
- new insn(s) and do the updates. */
- emit_insns_before (insns, insn);
+\f
+/* Integer list support. */
- if (basic_block_head[BLOCK_NUM (insn)] == insn)
- basic_block_head[BLOCK_NUM (insn)] = insns;
+/* Allocate a node from list *HEAD_PTR. */
- /* INCR will become a NOTE and INSN won't contain a
- use of ADDR. If a use of ADDR was just placed in
- the insn before INSN, make that the next use.
- Otherwise, invalidate it. */
- if (GET_CODE (PREV_INSN (insn)) == INSN
- && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
- && SET_SRC (PATTERN (PREV_INSN (insn))) == addr)
- reg_next_use[regno] = PREV_INSN (insn);
- else
- reg_next_use[regno] = 0;
+static int_list_ptr
+alloc_int_list_node (head_ptr)
+ int_list_block **head_ptr;
+{
+ struct int_list_block *first_blk = *head_ptr;
- addr = q;
- regno = REGNO (q);
+ if (first_blk == NULL || first_blk->nodes_left <= 0)
+ {
+ first_blk = (struct int_list_block *) xmalloc (sizeof (struct int_list_block));
+ first_blk->nodes_left = INT_LIST_NODES_IN_BLK;
+ first_blk->next = *head_ptr;
+ *head_ptr = first_blk;
+ }
- /* REGNO is now used in INCR which is below INSN, but
- it previously wasn't live here. If we don't mark
- it as needed, we'll put a REG_DEAD note for it
- on this insn, which is incorrect. */
- SET_REGNO_REG_SET (needed, regno);
+ first_blk->nodes_left--;
+ return &first_blk->nodes[first_blk->nodes_left];
+}
- /* If there are any calls between INSN and INCR, show
- that REGNO now crosses them. */
- for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
- if (GET_CODE (temp) == CALL_INSN)
- REG_N_CALLS_CROSSED (regno)++;
- }
- else
- return;
+/* Pointer to head of predecessor/successor block list. */
+static int_list_block *pred_int_list_blocks;
- /* If we haven't returned, it means we were able to make the
- auto-inc, so update the status. First, record that this insn
- has an implicit side effect. */
+/* Add a new node to integer list LIST with value VAL.
+ LIST is a pointer to a list object to allow for different implementations.
+ If *LIST is initially NULL, the list is empty.
+ The caller must not care whether the element is added to the front or
+ to the end of the list (to allow for different implementations). */
- REG_NOTES (insn)
- = gen_rtx (EXPR_LIST, REG_INC, addr, REG_NOTES (insn));
+static int_list_ptr
+add_int_list_node (blk_list, list, val)
+ int_list_block **blk_list;
+ int_list **list;
+ int val;
+{
+ int_list_ptr p = alloc_int_list_node (blk_list);
- /* Modify the old increment-insn to simply copy
- the already-incremented value of our register. */
- if (! validate_change (incr, &SET_SRC (set), addr, 0))
- abort ();
+ p->val = val;
+ p->next = *list;
+ *list = p;
+ return p;
+}
- /* If that makes it a no-op (copying the register into itself) delete
- it so it won't appear to be a "use" and a "set" of this
- register. */
- if (SET_DEST (set) == addr)
- {
- PUT_CODE (incr, NOTE);
- NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (incr) = 0;
- }
+/* Free the blocks of lists at BLK_LIST. */
- if (regno >= FIRST_PSEUDO_REGISTER)
- {
- /* Count an extra reference to the reg. When a reg is
- incremented, spilling it is worse, so we want to make
- that less likely. */
- REG_N_REFS (regno) += loop_depth;
+void
+free_int_list (blk_list)
+ int_list_block **blk_list;
+{
+ int_list_block *p, *next;
- /* Count the increment as a setting of the register,
- even though it isn't a SET in rtl. */
- REG_N_SETS (regno)++;
- }
- }
+ for (p = *blk_list; p != NULL; p = next)
+ {
+ next = p->next;
+ free (p);
}
+
+ /* Mark list as empty for the next function we compile. */
+ *blk_list = NULL;
}
-#endif /* AUTO_INC_DEC */
\f
-/* Scan expression X and store a 1-bit in LIVE for each reg it uses.
- This is done assuming the registers needed from X
- are those that have 1-bits in NEEDED.
-
- On the final pass, FINAL is 1. This means try for autoincrement
- and count the uses and deaths of each pseudo-reg.
+/* Predecessor/successor computation. */
- INSN is the containing instruction. If INSN is dead, this function is not
- called. */
+/* Mark PRED_BB a precessor of SUCC_BB,
+ and conversely SUCC_BB a successor of PRED_BB. */
static void
-mark_used_regs (needed, live, x, final, insn)
- regset needed;
- regset live;
- rtx x;
- int final;
- rtx insn;
+add_pred_succ (pred_bb, succ_bb, s_preds, s_succs, num_preds, num_succs)
+ int pred_bb;
+ int succ_bb;
+ int_list_ptr *s_preds;
+ int_list_ptr *s_succs;
+ int *num_preds;
+ int *num_succs;
{
- register RTX_CODE code;
- register int regno;
- int i;
+ if (succ_bb != EXIT_BLOCK)
+ {
+ add_int_list_node (&pred_int_list_blocks, &s_preds[succ_bb], pred_bb);
+ num_preds[succ_bb]++;
+ }
+ if (pred_bb != ENTRY_BLOCK)
+ {
+ add_int_list_node (&pred_int_list_blocks, &s_succs[pred_bb], succ_bb);
+ num_succs[pred_bb]++;
+ }
+}
- retry:
- code = GET_CODE (x);
- switch (code)
+/* Compute the predecessors and successors for each block. */
+void
+compute_preds_succs (s_preds, s_succs, num_preds, num_succs)
+ int_list_ptr *s_preds;
+ int_list_ptr *s_succs;
+ int *num_preds;
+ int *num_succs;
+{
+ int bb;
+
+ bzero ((char *) s_preds, n_basic_blocks * sizeof (int_list_ptr));
+ bzero ((char *) s_succs, n_basic_blocks * sizeof (int_list_ptr));
+ bzero ((char *) num_preds, n_basic_blocks * sizeof (int));
+ bzero ((char *) num_succs, n_basic_blocks * sizeof (int));
+
+ /* It's somewhat stupid to simply copy the information. The passes
+ which use this function ought to be changed to refer directly to
+ basic_block_succ and its relatives. */
+ for (bb = 0; bb < n_basic_blocks; bb++)
{
- case LABEL_REF:
- case SYMBOL_REF:
- case CONST_INT:
- case CONST:
- case CONST_DOUBLE:
- case PC:
- case ADDR_VEC:
- case ADDR_DIFF_VEC:
- case ASM_INPUT:
- return;
+ rtx jump = BLOCK_END (bb);
+ enum rtx_code code = GET_CODE (jump);
+ int_list_ptr p;
+
+ for (p = basic_block_succ[bb]; p; p = p->next)
+ add_pred_succ (bb, INT_LIST_VAL (p), s_preds, s_succs, num_preds,
+ num_succs);
+
+ /* If this is a RETURN insn or a conditional jump in the last
+ basic block, or a non-jump insn in the last basic block, then
+ this block reaches the exit block. */
+ if ((code == JUMP_INSN && GET_CODE (PATTERN (jump)) == RETURN)
+ || (((code == JUMP_INSN
+ && condjump_p (jump) && !simplejump_p (jump))
+ || code != JUMP_INSN)
+ && bb == n_basic_blocks - 1))
+ add_pred_succ (bb, EXIT_BLOCK, s_preds, s_succs, num_preds, num_succs);
+ }
-#ifdef HAVE_cc0
- case CC0:
- cc0_live = 1;
- return;
-#endif
+ add_pred_succ (ENTRY_BLOCK, 0, s_preds, s_succs, num_preds, num_succs);
+}
- case CLOBBER:
- /* If we are clobbering a MEM, mark any registers inside the address
- as being used. */
- if (GET_CODE (XEXP (x, 0)) == MEM)
- mark_used_regs (needed, live, XEXP (XEXP (x, 0), 0), final, insn);
- return;
+void
+dump_bb_data (file, preds, succs, live_info)
+ FILE *file;
+ int_list_ptr *preds;
+ int_list_ptr *succs;
+ int live_info;
+{
+ int bb;
+ int_list_ptr p;
- case MEM:
- /* Invalidate the data for the last MEM stored, but only if MEM is
- something that can be stored into. */
- if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
- && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
- ; /* needn't clear last_mem_set */
- else
- last_mem_set = 0;
+ fprintf (file, "BB data\n\n");
+ for (bb = 0; bb < n_basic_blocks; bb++)
+ {
+ fprintf (file, "BB %d, start %d, end %d\n", bb,
+ INSN_UID (BLOCK_HEAD (bb)), INSN_UID (BLOCK_END (bb)));
+ fprintf (file, " preds:");
+ for (p = preds[bb]; p != NULL; p = p->next)
+ {
+ int pred_bb = INT_LIST_VAL (p);
+ if (pred_bb == ENTRY_BLOCK)
+ fprintf (file, " entry");
+ else
+ fprintf (file, " %d", pred_bb);
+ }
+ fprintf (file, "\n");
+ fprintf (file, " succs:");
+ for (p = succs[bb]; p != NULL; p = p->next)
+ {
+ int succ_bb = INT_LIST_VAL (p);
+ if (succ_bb == EXIT_BLOCK)
+ fprintf (file, " exit");
+ else
+ fprintf (file, " %d", succ_bb);
+ }
+ if (live_info)
+ {
+ int regno;
+ fprintf (file, "\nRegisters live at start:");
+ for (regno = 0; regno < max_regno; regno++)
+ if (REGNO_REG_SET_P (basic_block_live_at_start[bb], regno))
+ fprintf (file, " %d", regno);
+ fprintf (file, "\n");
+ }
+ fprintf (file, "\n");
+ }
+ fprintf (file, "\n");
+}
-#ifdef AUTO_INC_DEC
- if (final)
- find_auto_inc (needed, x, insn);
-#endif
- break;
+void
+dump_sbitmap (file, bmap)
+ FILE *file;
+ sbitmap bmap;
+{
+ int i,j,n;
+ int set_size = bmap->size;
+ int total_bits = bmap->n_bits;
+
+ fprintf (file, " ");
+ for (i = n = 0; i < set_size && n < total_bits; i++)
+ {
+ for (j = 0; j < SBITMAP_ELT_BITS && n < total_bits; j++, n++)
+ {
+ if (n != 0 && n % 10 == 0)
+ fprintf (file, " ");
+ fprintf (file, "%d", (bmap->elms[i] & (1L << j)) != 0);
+ }
+ }
+ fprintf (file, "\n");
+}
+
+void
+dump_sbitmap_vector (file, title, subtitle, bmaps, n_maps)
+ FILE *file;
+ char *title, *subtitle;
+ sbitmap *bmaps;
+ int n_maps;
+{
+ int bb;
+
+ fprintf (file, "%s\n", title);
+ for (bb = 0; bb < n_maps; bb++)
+ {
+ fprintf (file, "%s %d\n", subtitle, bb);
+ dump_sbitmap (file, bmaps[bb]);
+ }
+ fprintf (file, "\n");
+}
+
+/* Free basic block data storage. */
+
+void
+free_bb_mem ()
+{
+ free_int_list (&pred_int_list_blocks);
+}
+\f
+/* Bitmap manipulation routines. */
+
+/* Allocate a simple bitmap of N_ELMS bits. */
+
+sbitmap
+sbitmap_alloc (n_elms)
+ int n_elms;
+{
+ int bytes, size, amt;
+ sbitmap bmap;
+
+ size = SBITMAP_SET_SIZE (n_elms);
+ bytes = size * sizeof (SBITMAP_ELT_TYPE);
+ amt = (sizeof (struct simple_bitmap_def)
+ + bytes - sizeof (SBITMAP_ELT_TYPE));
+ bmap = (sbitmap) xmalloc (amt);
+ bmap->n_bits = n_elms;
+ bmap->size = size;
+ bmap->bytes = bytes;
+ return bmap;
+}
+
+/* Allocate a vector of N_VECS bitmaps of N_ELMS bits. */
- case SUBREG:
- if (GET_CODE (SUBREG_REG (x)) == REG
- && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
- && (GET_MODE_SIZE (GET_MODE (x))
- != GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)))))
- REG_CHANGES_SIZE (REGNO (SUBREG_REG (x))) = 1;
+sbitmap *
+sbitmap_vector_alloc (n_vecs, n_elms)
+ int n_vecs, n_elms;
+{
+ int i, bytes, offset, elm_bytes, size, amt, vector_bytes;
+ sbitmap *bitmap_vector;
+
+ size = SBITMAP_SET_SIZE (n_elms);
+ bytes = size * sizeof (SBITMAP_ELT_TYPE);
+ elm_bytes = (sizeof (struct simple_bitmap_def)
+ + bytes - sizeof (SBITMAP_ELT_TYPE));
+ vector_bytes = n_vecs * sizeof (sbitmap *);
+
+ /* Round up `vector_bytes' to account for the alignment requirements
+ of an sbitmap. One could allocate the vector-table and set of sbitmaps
+ separately, but that requires maintaining two pointers or creating
+ a cover struct to hold both pointers (so our result is still just
+ one pointer). Neither is a bad idea, but this is simpler for now. */
+ {
+ /* Based on DEFAULT_ALIGNMENT computation in obstack.c. */
+ struct { char x; SBITMAP_ELT_TYPE y; } align;
+ int alignment = (char *) & align.y - & align.x;
+ vector_bytes = (vector_bytes + alignment - 1) & ~ (alignment - 1);
+ }
- /* While we're here, optimize this case. */
- x = SUBREG_REG (x);
+ amt = vector_bytes + (n_vecs * elm_bytes);
+ bitmap_vector = (sbitmap *) xmalloc (amt);
- /* In case the SUBREG is not of a register, don't optimize */
- if (GET_CODE (x) != REG)
- {
- mark_used_regs (needed, live, x, final, insn);
- return;
- }
+ for (i = 0, offset = vector_bytes;
+ i < n_vecs;
+ i++, offset += elm_bytes)
+ {
+ sbitmap b = (sbitmap) ((char *) bitmap_vector + offset);
+ bitmap_vector[i] = b;
+ b->n_bits = n_elms;
+ b->size = size;
+ b->bytes = bytes;
+ }
- /* ... fall through ... */
+ return bitmap_vector;
+}
- case REG:
- /* See a register other than being set
- => mark it as needed. */
+/* Copy sbitmap SRC to DST. */
- regno = REGNO (x);
- {
- int some_needed = REGNO_REG_SET_P (needed, regno);
- int some_not_needed = ! some_needed;
+void
+sbitmap_copy (dst, src)
+ sbitmap dst, src;
+{
+ bcopy ((PTR) src->elms, (PTR) dst->elms, sizeof (SBITMAP_ELT_TYPE) * dst->size);
+}
- SET_REGNO_REG_SET (live, regno);
+/* Zero all elements in a bitmap. */
- /* A hard reg in a wide mode may really be multiple registers.
- If so, mark all of them just like the first. */
- if (regno < FIRST_PSEUDO_REGISTER)
- {
- int n;
+void
+sbitmap_zero (bmap)
+ sbitmap bmap;
+{
+ bzero ((char *) bmap->elms, bmap->bytes);
+}
- /* For stack ptr or fixed arg pointer,
- nothing below can be necessary, so waste no more time. */
- if (regno == STACK_POINTER_REGNUM
-#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
- || regno == HARD_FRAME_POINTER_REGNUM
-#endif
-#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
- || (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
-#endif
- || regno == FRAME_POINTER_REGNUM)
- {
- /* If this is a register we are going to try to eliminate,
- don't mark it live here. If we are successful in
- eliminating it, it need not be live unless it is used for
- pseudos, in which case it will have been set live when
- it was allocated to the pseudos. If the register will not
- be eliminated, reload will set it live at that point. */
+/* Set to ones all elements in a bitmap. */
- if (! TEST_HARD_REG_BIT (elim_reg_set, regno))
- regs_ever_live[regno] = 1;
- return;
- }
- /* No death notes for global register variables;
- their values are live after this function exits. */
- if (global_regs[regno])
- {
- if (final)
- reg_next_use[regno] = insn;
- return;
- }
+void
+sbitmap_ones (bmap)
+ sbitmap bmap;
+{
+ memset (bmap->elms, -1, bmap->bytes);
+}
- n = HARD_REGNO_NREGS (regno, GET_MODE (x));
- while (--n > 0)
- {
- int regno_n = regno + n;
- int needed_regno = REGNO_REG_SET_P (needed, regno_n);
+/* Zero a vector of N_VECS bitmaps. */
- SET_REGNO_REG_SET (live, regno_n);
- some_needed |= needed_regno;
- some_not_needed |= ! needed_regno;
- }
- }
- if (final)
- {
- /* Record where each reg is used, so when the reg
- is set we know the next insn that uses it. */
+void
+sbitmap_vector_zero (bmap, n_vecs)
+ sbitmap *bmap;
+ int n_vecs;
+{
+ int i;
- reg_next_use[regno] = insn;
+ for (i = 0; i < n_vecs; i++)
+ sbitmap_zero (bmap[i]);
+}
- if (regno < FIRST_PSEUDO_REGISTER)
- {
- /* If a hard reg is being used,
- record that this function does use it. */
+/* Set to ones a vector of N_VECS bitmaps. */
- i = HARD_REGNO_NREGS (regno, GET_MODE (x));
- if (i == 0)
- i = 1;
- do
- regs_ever_live[regno + --i] = 1;
- while (i > 0);
- }
- else
- {
- /* Keep track of which basic block each reg appears in. */
+void
+sbitmap_vector_ones (bmap, n_vecs)
+ sbitmap *bmap;
+ int n_vecs;
+{
+ int i;
- register int blocknum = BLOCK_NUM (insn);
+ for (i = 0; i < n_vecs; i++)
+ sbitmap_ones (bmap[i]);
+}
- if (REG_BASIC_BLOCK (regno) == REG_BLOCK_UNKNOWN)
- REG_BASIC_BLOCK (regno) = blocknum;
- else if (REG_BASIC_BLOCK (regno) != blocknum)
- REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL;
+/* Set DST to be A union (B - C).
+ DST = A | (B & ~C).
+ Return non-zero if any change is made. */
- /* Count (weighted) number of uses of each reg. */
+int
+sbitmap_union_of_diff (dst, a, b, c)
+ sbitmap dst, a, b, c;
+{
+ int i,changed;
+ sbitmap_ptr dstp, ap, bp, cp;
+
+ changed = 0;
+ dstp = dst->elms;
+ ap = a->elms;
+ bp = b->elms;
+ cp = c->elms;
+ for (i = 0; i < dst->size; i++)
+ {
+ SBITMAP_ELT_TYPE tmp = *ap | (*bp & ~*cp);
+ if (*dstp != tmp)
+ changed = 1;
+ *dstp = tmp;
+ dstp++; ap++; bp++; cp++;
+ }
+ return changed;
+}
- REG_N_REFS (regno) += loop_depth;
- }
+/* Set bitmap DST to the bitwise negation of the bitmap SRC. */
- /* Record and count the insns in which a reg dies.
- If it is used in this insn and was dead below the insn
- then it dies in this insn. If it was set in this insn,
- we do not make a REG_DEAD note; likewise if we already
- made such a note. */
+void
+sbitmap_not (dst, src)
+ sbitmap dst, src;
+{
+ int i;
+ sbitmap_ptr dstp, ap;
- if (some_not_needed
- && ! dead_or_set_p (insn, x)
-#if 0
- && (regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno])
-#endif
- )
- {
- /* Check for the case where the register dying partially
- overlaps the register set by this insn. */
- if (regno < FIRST_PSEUDO_REGISTER
- && HARD_REGNO_NREGS (regno, GET_MODE (x)) > 1)
- {
- int n = HARD_REGNO_NREGS (regno, GET_MODE (x));
- while (--n >= 0)
- some_needed |= dead_or_set_regno_p (insn, regno + n);
- }
+ dstp = dst->elms;
+ ap = src->elms;
+ for (i = 0; i < dst->size; i++)
+ {
+ SBITMAP_ELT_TYPE tmp = ~(*ap);
+ *dstp = tmp;
+ dstp++; ap++;
+ }
+}
- /* If none of the words in X is needed, make a REG_DEAD
- note. Otherwise, we must make partial REG_DEAD notes. */
- if (! some_needed)
- {
- REG_NOTES (insn)
- = gen_rtx (EXPR_LIST, REG_DEAD, x, REG_NOTES (insn));
- REG_N_DEATHS (regno)++;
- }
- else
- {
- int i;
+/* Set the bits in DST to be the difference between the bits
+ in A and the bits in B. i.e. dst = a - b.
+ The - operator is implemented as a & (~b). */
- /* Don't make a REG_DEAD note for a part of a register
- that is set in the insn. */
+void
+sbitmap_difference (dst, a, b)
+ sbitmap dst, a, b;
+{
+ int i;
+ sbitmap_ptr dstp, ap, bp;
- for (i = HARD_REGNO_NREGS (regno, GET_MODE (x)) - 1;
- i >= 0; i--)
- if (!REGNO_REG_SET_P (needed, regno + i)
- && ! dead_or_set_regno_p (insn, regno + i))
- REG_NOTES (insn)
- = gen_rtx (EXPR_LIST, REG_DEAD,
- gen_rtx (REG, reg_raw_mode[regno + i],
- regno + i),
- REG_NOTES (insn));
- }
- }
- }
- }
- return;
+ dstp = dst->elms;
+ ap = a->elms;
+ bp = b->elms;
+ for (i = 0; i < dst->size; i++)
+ *dstp++ = *ap++ & (~*bp++);
+}
- case SET:
- {
- register rtx testreg = SET_DEST (x);
- int mark_dest = 0;
+/* Set DST to be (A and B)).
+ Return non-zero if any change is made. */
- /* If storing into MEM, don't show it as being used. But do
- show the address as being used. */
- if (GET_CODE (testreg) == MEM)
- {
-#ifdef AUTO_INC_DEC
- if (final)
- find_auto_inc (needed, testreg, insn);
-#endif
- mark_used_regs (needed, live, XEXP (testreg, 0), final, insn);
- mark_used_regs (needed, live, SET_SRC (x), final, insn);
- return;
- }
-
- /* Storing in STRICT_LOW_PART is like storing in a reg
- in that this SET might be dead, so ignore it in TESTREG.
- but in some other ways it is like using the reg.
+int
+sbitmap_a_and_b (dst, a, b)
+ sbitmap dst, a, b;
+{
+ int i,changed;
+ sbitmap_ptr dstp, ap, bp;
+
+ changed = 0;
+ dstp = dst->elms;
+ ap = a->elms;
+ bp = b->elms;
+ for (i = 0; i < dst->size; i++)
+ {
+ SBITMAP_ELT_TYPE tmp = *ap & *bp;
+ if (*dstp != tmp)
+ changed = 1;
+ *dstp = tmp;
+ dstp++; ap++; bp++;
+ }
+ return changed;
+}
+/* Set DST to be (A or B)).
+ Return non-zero if any change is made. */
- Storing in a SUBREG or a bit field is like storing the entire
- register in that if the register's value is not used
- then this SET is not needed. */
- while (GET_CODE (testreg) == STRICT_LOW_PART
- || GET_CODE (testreg) == ZERO_EXTRACT
- || GET_CODE (testreg) == SIGN_EXTRACT
- || GET_CODE (testreg) == SUBREG)
- {
- if (GET_CODE (testreg) == SUBREG
- && GET_CODE (SUBREG_REG (testreg)) == REG
- && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
- && (GET_MODE_SIZE (GET_MODE (testreg))
- != GET_MODE_SIZE (GET_MODE (SUBREG_REG (testreg)))))
- REG_CHANGES_SIZE (REGNO (SUBREG_REG (testreg))) = 1;
+int
+sbitmap_a_or_b (dst, a, b)
+ sbitmap dst, a, b;
+{
+ int i,changed;
+ sbitmap_ptr dstp, ap, bp;
+
+ changed = 0;
+ dstp = dst->elms;
+ ap = a->elms;
+ bp = b->elms;
+ for (i = 0; i < dst->size; i++)
+ {
+ SBITMAP_ELT_TYPE tmp = *ap | *bp;
+ if (*dstp != tmp)
+ changed = 1;
+ *dstp = tmp;
+ dstp++; ap++; bp++;
+ }
+ return changed;
+}
- /* Modifying a single register in an alternate mode
- does not use any of the old value. But these other
- ways of storing in a register do use the old value. */
- if (GET_CODE (testreg) == SUBREG
- && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
- ;
- else
- mark_dest = 1;
+/* Set DST to be (A or (B and C)).
+ Return non-zero if any change is made. */
- testreg = XEXP (testreg, 0);
- }
+int
+sbitmap_a_or_b_and_c (dst, a, b, c)
+ sbitmap dst, a, b, c;
+{
+ int i,changed;
+ sbitmap_ptr dstp, ap, bp, cp;
+
+ changed = 0;
+ dstp = dst->elms;
+ ap = a->elms;
+ bp = b->elms;
+ cp = c->elms;
+ for (i = 0; i < dst->size; i++)
+ {
+ SBITMAP_ELT_TYPE tmp = *ap | (*bp & *cp);
+ if (*dstp != tmp)
+ changed = 1;
+ *dstp = tmp;
+ dstp++; ap++; bp++; cp++;
+ }
+ return changed;
+}
- /* If this is a store into a register,
- recursively scan the value being stored. */
+/* Set DST to be (A ann (B or C)).
+ Return non-zero if any change is made. */
- if (GET_CODE (testreg) == REG
- && (regno = REGNO (testreg), regno != FRAME_POINTER_REGNUM)
-#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
- && regno != HARD_FRAME_POINTER_REGNUM
-#endif
-#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
- && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
-#endif
- )
- /* We used to exclude global_regs here, but that seems wrong.
- Storing in them is like storing in mem. */
- {
- mark_used_regs (needed, live, SET_SRC (x), final, insn);
- if (mark_dest)
- mark_used_regs (needed, live, SET_DEST (x), final, insn);
- return;
- }
- }
- break;
+int
+sbitmap_a_and_b_or_c (dst, a, b, c)
+ sbitmap dst, a, b, c;
+{
+ int i,changed;
+ sbitmap_ptr dstp, ap, bp, cp;
+
+ changed = 0;
+ dstp = dst->elms;
+ ap = a->elms;
+ bp = b->elms;
+ cp = c->elms;
+ for (i = 0; i < dst->size; i++)
+ {
+ SBITMAP_ELT_TYPE tmp = *ap & (*bp | *cp);
+ if (*dstp != tmp)
+ changed = 1;
+ *dstp = tmp;
+ dstp++; ap++; bp++; cp++;
+ }
+ return changed;
+}
- case RETURN:
- /* If exiting needs the right stack value, consider this insn as
- using the stack pointer. In any event, consider it as using
- all global registers and all registers used by return. */
+/* Set the bitmap DST to the intersection of SRC of all predecessors or
+ successors of block number BB (PRED_SUCC says which). */
-#ifdef EXIT_IGNORE_STACK
- if (! EXIT_IGNORE_STACK
- || (! FRAME_POINTER_REQUIRED && flag_omit_frame_pointer))
-#endif
- SET_REGNO_REG_SET (live, STACK_POINTER_REGNUM);
+void
+sbitmap_intersect_of_predsucc (dst, src, bb, pred_succ)
+ sbitmap dst;
+ sbitmap *src;
+ int bb;
+ int_list_ptr *pred_succ;
+{
+ int_list_ptr ps;
+ int ps_bb;
+ int set_size = dst->size;
- for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
- if (global_regs[i]
-#ifdef EPILOGUE_USES
- || EPILOGUE_USES (i)
-#endif
- )
- SET_REGNO_REG_SET (live, i);
+ ps = pred_succ[bb];
+
+ /* It is possible that there are no predecessors(/successors).
+ This can happen for example in unreachable code. */
+
+ if (ps == NULL)
+ {
+ /* In APL-speak this is the `and' reduction of the empty set and thus
+ the result is the identity for `and'. */
+ sbitmap_ones (dst);
+ return;
+ }
+
+ /* Set result to first predecessor/successor. */
+
+ for ( ; ps != NULL; ps = ps->next)
+ {
+ ps_bb = INT_LIST_VAL (ps);
+ if (ps_bb == ENTRY_BLOCK || ps_bb == EXIT_BLOCK)
+ continue;
+ sbitmap_copy (dst, src[ps_bb]);
+ /* Break out since we're only doing first predecessor. */
break;
}
+ if (ps == NULL)
+ return;
- /* Recursively scan the operands of this expression. */
+ /* Now do the remaining predecessors/successors. */
- {
- register char *fmt = GET_RTX_FORMAT (code);
- register int i;
-
- for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
- {
- if (fmt[i] == 'e')
- {
- /* Tail recursive case: save a function call level. */
- if (i == 0)
- {
- x = XEXP (x, 0);
- goto retry;
- }
- mark_used_regs (needed, live, XEXP (x, i), final, insn);
- }
- else if (fmt[i] == 'E')
- {
- register int j;
- for (j = 0; j < XVECLEN (x, i); j++)
- mark_used_regs (needed, live, XVECEXP (x, i, j), final, insn);
- }
- }
- }
+ for (ps = ps->next; ps != NULL; ps = ps->next)
+ {
+ int i;
+ sbitmap_ptr p,r;
+
+ ps_bb = INT_LIST_VAL (ps);
+ if (ps_bb == ENTRY_BLOCK || ps_bb == EXIT_BLOCK)
+ continue;
+
+ p = src[ps_bb]->elms;
+ r = dst->elms;
+
+ for (i = 0; i < set_size; i++)
+ *r++ &= *p++;
+ }
}
-\f
-#ifdef AUTO_INC_DEC
-static int
-try_pre_increment_1 (insn)
- rtx insn;
+/* Set the bitmap DST to the intersection of SRC of all predecessors
+ of block number BB. */
+
+void
+sbitmap_intersect_of_predecessors (dst, src, bb, s_preds)
+ sbitmap dst;
+ sbitmap *src;
+ int bb;
+ int_list_ptr *s_preds;
{
- /* Find the next use of this reg. If in same basic block,
- make it do pre-increment or pre-decrement if appropriate. */
- rtx x = PATTERN (insn);
- HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
- * INTVAL (XEXP (SET_SRC (x), 1)));
- int regno = REGNO (SET_DEST (x));
- rtx y = reg_next_use[regno];
- if (y != 0
- && BLOCK_NUM (y) == BLOCK_NUM (insn)
- /* Don't do this if the reg dies, or gets set in y; a standard addressing
- mode would be better. */
- && ! dead_or_set_p (y, SET_DEST (x))
- && try_pre_increment (y, SET_DEST (PATTERN (insn)),
- amount))
- {
- /* We have found a suitable auto-increment
- and already changed insn Y to do it.
- So flush this increment-instruction. */
- PUT_CODE (insn, NOTE);
- NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (insn) = 0;
- /* Count a reference to this reg for the increment
- insn we are deleting. When a reg is incremented.
- spilling it is worse, so we want to make that
- less likely. */
- if (regno >= FIRST_PSEUDO_REGISTER)
- {
- REG_N_REFS (regno) += loop_depth;
- REG_N_SETS (regno)++;
- }
- return 1;
- }
- return 0;
+ sbitmap_intersect_of_predsucc (dst, src, bb, s_preds);
}
-/* Try to change INSN so that it does pre-increment or pre-decrement
- addressing on register REG in order to add AMOUNT to REG.
- AMOUNT is negative for pre-decrement.
- Returns 1 if the change could be made.
- This checks all about the validity of the result of modifying INSN. */
+/* Set the bitmap DST to the intersection of SRC of all successors
+ of block number BB. */
-static int
-try_pre_increment (insn, reg, amount)
- rtx insn, reg;
- HOST_WIDE_INT amount;
+void
+sbitmap_intersect_of_successors (dst, src, bb, s_succs)
+ sbitmap dst;
+ sbitmap *src;
+ int bb;
+ int_list_ptr *s_succs;
{
- register rtx use;
+ sbitmap_intersect_of_predsucc (dst, src, bb, s_succs);
+}
- /* Nonzero if we can try to make a pre-increment or pre-decrement.
- For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
- int pre_ok = 0;
- /* Nonzero if we can try to make a post-increment or post-decrement.
- For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
- It is possible for both PRE_OK and POST_OK to be nonzero if the machine
- supports both pre-inc and post-inc, or both pre-dec and post-dec. */
- int post_ok = 0;
+/* Set the bitmap DST to the union of SRC of all predecessors/successors of
+ block number BB. */
- /* Nonzero if the opportunity actually requires post-inc or post-dec. */
- int do_post = 0;
+void
+sbitmap_union_of_predsucc (dst, src, bb, pred_succ)
+ sbitmap dst;
+ sbitmap *src;
+ int bb;
+ int_list_ptr *pred_succ;
+{
+ int_list_ptr ps;
+ int ps_bb;
+ int set_size = dst->size;
- /* From the sign of increment, see which possibilities are conceivable
- on this target machine. */
-#ifdef HAVE_PRE_INCREMENT
- if (amount > 0)
- pre_ok = 1;
-#endif
-#ifdef HAVE_POST_INCREMENT
- if (amount > 0)
- post_ok = 1;
-#endif
+ ps = pred_succ[bb];
-#ifdef HAVE_PRE_DECREMENT
- if (amount < 0)
- pre_ok = 1;
-#endif
-#ifdef HAVE_POST_DECREMENT
- if (amount < 0)
- post_ok = 1;
-#endif
+ /* It is possible that there are no predecessors(/successors).
+ This can happen for example in unreachable code. */
- if (! (pre_ok || post_ok))
- return 0;
+ if (ps == NULL)
+ {
+ /* In APL-speak this is the `or' reduction of the empty set and thus
+ the result is the identity for `or'. */
+ sbitmap_zero (dst);
+ return;
+ }
- /* It is not safe to add a side effect to a jump insn
- because if the incremented register is spilled and must be reloaded
- there would be no way to store the incremented value back in memory. */
+ /* Set result to first predecessor/successor. */
- if (GET_CODE (insn) == JUMP_INSN)
- return 0;
+ for ( ; ps != NULL; ps = ps->next)
+ {
+ ps_bb = INT_LIST_VAL (ps);
+ if (ps_bb == ENTRY_BLOCK || ps_bb == EXIT_BLOCK)
+ continue;
+ sbitmap_copy (dst, src[ps_bb]);
+ /* Break out since we're only doing first predecessor. */
+ break;
+ }
+ if (ps == NULL)
+ return;
- use = 0;
- if (pre_ok)
- use = find_use_as_address (PATTERN (insn), reg, 0);
- if (post_ok && (use == 0 || use == (rtx) 1))
+ /* Now do the remaining predecessors/successors. */
+
+ for (ps = ps->next; ps != NULL; ps = ps->next)
{
- use = find_use_as_address (PATTERN (insn), reg, -amount);
- do_post = 1;
+ int i;
+ sbitmap_ptr p,r;
+
+ ps_bb = INT_LIST_VAL (ps);
+ if (ps_bb == ENTRY_BLOCK || ps_bb == EXIT_BLOCK)
+ continue;
+
+ p = src[ps_bb]->elms;
+ r = dst->elms;
+
+ for (i = 0; i < set_size; i++)
+ *r++ |= *p++;
}
+}
- if (use == 0 || use == (rtx) 1)
- return 0;
+/* Set the bitmap DST to the union of SRC of all predecessors of
+ block number BB. */
- if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
- return 0;
+void
+sbitmap_union_of_predecessors (dst, src, bb, s_preds)
+ sbitmap dst;
+ sbitmap *src;
+ int bb;
+ int_list_ptr *s_preds;
+{
+ sbitmap_union_of_predsucc (dst, src, bb, s_preds);
+}
- /* See if this combination of instruction and addressing mode exists. */
- if (! validate_change (insn, &XEXP (use, 0),
- gen_rtx (amount > 0
- ? (do_post ? POST_INC : PRE_INC)
- : (do_post ? POST_DEC : PRE_DEC),
- Pmode, reg), 0))
- return 0;
+/* Set the bitmap DST to the union of SRC of all predecessors of
+ block number BB. */
- /* Record that this insn now has an implicit side effect on X. */
- REG_NOTES (insn) = gen_rtx (EXPR_LIST, REG_INC, reg, REG_NOTES (insn));
- return 1;
+void
+sbitmap_union_of_successors (dst, src, bb, s_succ)
+ sbitmap dst;
+ sbitmap *src;
+ int bb;
+ int_list_ptr *s_succ;
+{
+ sbitmap_union_of_predsucc (dst, src, bb, s_succ);
}
-#endif /* AUTO_INC_DEC */
-\f
-/* Find the place in the rtx X where REG is used as a memory address.
- Return the MEM rtx that so uses it.
- If PLUSCONST is nonzero, search instead for a memory address equivalent to
- (plus REG (const_int PLUSCONST)).
+/* Compute dominator relationships. */
+void
+compute_dominators (dominators, post_dominators, s_preds, s_succs)
+ sbitmap *dominators;
+ sbitmap *post_dominators;
+ int_list_ptr *s_preds;
+ int_list_ptr *s_succs;
+{
+ int bb, changed, passes;
+ sbitmap *temp_bitmap;
- If such an address does not appear, return 0.
- If REG appears more than once, or is used other than in such an address,
- return (rtx)1. */
+ temp_bitmap = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
+ sbitmap_vector_ones (dominators, n_basic_blocks);
+ sbitmap_vector_ones (post_dominators, n_basic_blocks);
+ sbitmap_vector_zero (temp_bitmap, n_basic_blocks);
-rtx
-find_use_as_address (x, reg, plusconst)
- register rtx x;
- rtx reg;
- HOST_WIDE_INT plusconst;
+ sbitmap_zero (dominators[0]);
+ SET_BIT (dominators[0], 0);
+
+ sbitmap_zero (post_dominators[n_basic_blocks-1]);
+ SET_BIT (post_dominators[n_basic_blocks-1], 0);
+
+ passes = 0;
+ changed = 1;
+ while (changed)
+ {
+ changed = 0;
+ for (bb = 1; bb < n_basic_blocks; bb++)
+ {
+ sbitmap_intersect_of_predecessors (temp_bitmap[bb], dominators,
+ bb, s_preds);
+ SET_BIT (temp_bitmap[bb], bb);
+ changed |= sbitmap_a_and_b (dominators[bb],
+ dominators[bb],
+ temp_bitmap[bb]);
+ sbitmap_intersect_of_successors (temp_bitmap[bb], post_dominators,
+ bb, s_succs);
+ SET_BIT (temp_bitmap[bb], bb);
+ changed |= sbitmap_a_and_b (post_dominators[bb],
+ post_dominators[bb],
+ temp_bitmap[bb]);
+ }
+ passes++;
+ }
+
+ free (temp_bitmap);
+}
+
+/* Count for a single SET rtx, X. */
+
+static void
+count_reg_sets_1 (x)
+ rtx x;
{
- enum rtx_code code = GET_CODE (x);
- char *fmt = GET_RTX_FORMAT (code);
- register int i;
- register rtx value = 0;
- register rtx tem;
+ register int regno;
+ register rtx reg = SET_DEST (x);
- if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
- return x;
+ /* Find the register that's set/clobbered. */
+ while (GET_CODE (reg) == SUBREG || GET_CODE (reg) == ZERO_EXTRACT
+ || GET_CODE (reg) == SIGN_EXTRACT
+ || GET_CODE (reg) == STRICT_LOW_PART)
+ reg = XEXP (reg, 0);
- if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
- && XEXP (XEXP (x, 0), 0) == reg
- && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
- && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
- return x;
+ if (GET_CODE (reg) == PARALLEL
+ && GET_MODE (reg) == BLKmode)
+ {
+ register int i;
+ for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
+ count_reg_sets_1 (XVECEXP (reg, 0, i));
+ return;
+ }
- if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
+ if (GET_CODE (reg) == REG)
{
- /* If REG occurs inside a MEM used in a bit-field reference,
- that is unacceptable. */
- if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
- return (rtx) (HOST_WIDE_INT) 1;
+ regno = REGNO (reg);
+ if (regno >= FIRST_PSEUDO_REGISTER)
+ {
+ /* Count (weighted) references, stores, etc. This counts a
+ register twice if it is modified, but that is correct. */
+ REG_N_SETS (regno)++;
+
+ REG_N_REFS (regno) += loop_depth;
+ }
+ }
+}
+
+/* Increment REG_N_SETS for each SET or CLOBBER found in X; also increment
+ REG_N_REFS by the current loop depth for each SET or CLOBBER found. */
+
+static void
+count_reg_sets (x)
+ rtx x;
+{
+ register RTX_CODE code = GET_CODE (x);
+
+ if (code == SET || code == CLOBBER)
+ count_reg_sets_1 (x);
+ else if (code == PARALLEL)
+ {
+ register int i;
+ for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
+ {
+ code = GET_CODE (XVECEXP (x, 0, i));
+ if (code == SET || code == CLOBBER)
+ count_reg_sets_1 (XVECEXP (x, 0, i));
+ }
}
+}
- if (x == reg)
- return (rtx) (HOST_WIDE_INT) 1;
+/* Increment REG_N_REFS by the current loop depth each register reference
+ found in X. */
- for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+static void
+count_reg_references (x)
+ rtx x;
+{
+ register RTX_CODE code;
+
+ retry:
+ code = GET_CODE (x);
+ switch (code)
{
- if (fmt[i] == 'e')
- {
- tem = find_use_as_address (XEXP (x, i), reg, plusconst);
- if (value == 0)
- value = tem;
- else if (tem != 0)
- return (rtx) (HOST_WIDE_INT) 1;
- }
- if (fmt[i] == 'E')
+ case LABEL_REF:
+ case SYMBOL_REF:
+ case CONST_INT:
+ case CONST:
+ case CONST_DOUBLE:
+ case PC:
+ case ADDR_VEC:
+ case ADDR_DIFF_VEC:
+ case ASM_INPUT:
+ return;
+
+#ifdef HAVE_cc0
+ case CC0:
+ return;
+#endif
+
+ case CLOBBER:
+ /* If we are clobbering a MEM, mark any registers inside the address
+ as being used. */
+ if (GET_CODE (XEXP (x, 0)) == MEM)
+ count_reg_references (XEXP (XEXP (x, 0), 0));
+ return;
+
+ case SUBREG:
+ /* While we're here, optimize this case. */
+ x = SUBREG_REG (x);
+
+ /* In case the SUBREG is not of a register, don't optimize */
+ if (GET_CODE (x) != REG)
{
- register int j;
- for (j = XVECLEN (x, i) - 1; j >= 0; j--)
- {
- tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
- if (value == 0)
- value = tem;
- else if (tem != 0)
- return (rtx) (HOST_WIDE_INT) 1;
- }
+ count_reg_references (x);
+ return;
}
- }
-
- return value;
-}
-\f
-/* Write information about registers and basic blocks into FILE.
- This is part of making a debugging dump. */
-void
-dump_flow_info (file)
- FILE *file;
-{
- register int i;
- static char *reg_class_names[] = REG_CLASS_NAMES;
+ /* ... fall through ... */
- fprintf (file, "%d registers.\n", max_regno);
+ case REG:
+ if (REGNO (x) >= FIRST_PSEUDO_REGISTER)
+ REG_N_REFS (REGNO (x)) += loop_depth;
+ return;
- for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
- if (REG_N_REFS (i))
+ case SET:
{
- enum reg_class class, altclass;
- fprintf (file, "\nRegister %d used %d times across %d insns",
- i, REG_N_REFS (i), REG_LIVE_LENGTH (i));
- if (REG_BASIC_BLOCK (i) >= 0)
- fprintf (file, " in block %d", REG_BASIC_BLOCK (i));
- if (REG_N_DEATHS (i) != 1)
- fprintf (file, "; dies in %d places", REG_N_DEATHS (i));
- if (REG_N_CALLS_CROSSED (i) == 1)
- fprintf (file, "; crosses 1 call");
- else if (REG_N_CALLS_CROSSED (i))
- fprintf (file, "; crosses %d calls", REG_N_CALLS_CROSSED (i));
- if (PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD)
- fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i));
- class = reg_preferred_class (i);
- altclass = reg_alternate_class (i);
- if (class != GENERAL_REGS || altclass != ALL_REGS)
+ register rtx testreg = SET_DEST (x);
+ int mark_dest = 0;
+
+ /* If storing into MEM, don't show it as being used. But do
+ show the address as being used. */
+ if (GET_CODE (testreg) == MEM)
{
- if (altclass == ALL_REGS || class == ALL_REGS)
- fprintf (file, "; pref %s", reg_class_names[(int) class]);
- else if (altclass == NO_REGS)
- fprintf (file, "; %s or none", reg_class_names[(int) class]);
+ count_reg_references (XEXP (testreg, 0));
+ count_reg_references (SET_SRC (x));
+ return;
+ }
+
+ /* Storing in STRICT_LOW_PART is like storing in a reg
+ in that this SET might be dead, so ignore it in TESTREG.
+ but in some other ways it is like using the reg.
+
+ Storing in a SUBREG or a bit field is like storing the entire
+ register in that if the register's value is not used
+ then this SET is not needed. */
+ while (GET_CODE (testreg) == STRICT_LOW_PART
+ || GET_CODE (testreg) == ZERO_EXTRACT
+ || GET_CODE (testreg) == SIGN_EXTRACT
+ || GET_CODE (testreg) == SUBREG)
+ {
+ /* Modifying a single register in an alternate mode
+ does not use any of the old value. But these other
+ ways of storing in a register do use the old value. */
+ if (GET_CODE (testreg) == SUBREG
+ && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
+ ;
else
- fprintf (file, "; pref %s, else %s",
- reg_class_names[(int) class],
- reg_class_names[(int) altclass]);
+ mark_dest = 1;
+
+ testreg = XEXP (testreg, 0);
+ }
+
+ /* If this is a store into a register,
+ recursively scan the value being stored. */
+
+ if ((GET_CODE (testreg) == PARALLEL
+ && GET_MODE (testreg) == BLKmode)
+ || GET_CODE (testreg) == REG)
+ {
+ count_reg_references (SET_SRC (x));
+ if (mark_dest)
+ count_reg_references (SET_DEST (x));
+ return;
}
- if (REGNO_POINTER_FLAG (i))
- fprintf (file, "; pointer");
- fprintf (file, ".\n");
}
- fprintf (file, "\n%d basic blocks.\n", n_basic_blocks);
- for (i = 0; i < n_basic_blocks; i++)
- {
- register rtx head, jump;
- register int regno;
- fprintf (file, "\nBasic block %d: first insn %d, last %d.\n",
- i,
- INSN_UID (basic_block_head[i]),
- INSN_UID (basic_block_end[i]));
- /* The control flow graph's storage is freed
- now when flow_analysis returns.
- Don't try to print it if it is gone. */
- if (basic_block_drops_in)
- {
- fprintf (file, "Reached from blocks: ");
- head = basic_block_head[i];
- if (GET_CODE (head) == CODE_LABEL)
- for (jump = LABEL_REFS (head);
- jump != head;
- jump = LABEL_NEXTREF (jump))
+ break;
+
+ default:
+ break;
+ }
+
+ /* Recursively scan the operands of this expression. */
+
+ {
+ register char *fmt = GET_RTX_FORMAT (code);
+ register int i;
+
+ for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+ {
+ if (fmt[i] == 'e')
+ {
+ /* Tail recursive case: save a function call level. */
+ if (i == 0)
{
- register int from_block = BLOCK_NUM (CONTAINING_INSN (jump));
- fprintf (file, " %d", from_block);
+ x = XEXP (x, 0);
+ goto retry;
}
- if (basic_block_drops_in[i])
- fprintf (file, " previous");
- }
- fprintf (file, "\nRegisters live at start:");
- for (regno = 0; regno < max_regno; regno++)
- if (REGNO_REG_SET_P (basic_block_live_at_start[i], regno))
- fprintf (file, " %d", regno);
- fprintf (file, "\n");
- }
- fprintf (file, "\n");
+ count_reg_references (XEXP (x, i));
+ }
+ else if (fmt[i] == 'E')
+ {
+ register int j;
+ for (j = 0; j < XVECLEN (x, i); j++)
+ count_reg_references (XVECEXP (x, i, j));
+ }
+ }
+ }
}
-\f
-/* Like print_rtl, but also print out live information for the start of each
- basic block. */
+/* Recompute register set/reference counts immediately prior to register
+ allocation.
+
+ This avoids problems with set/reference counts changing to/from values
+ which have special meanings to the register allocators.
+
+ Additionally, the reference counts are the primary component used by the
+ register allocators to prioritize pseudos for allocation to hard regs.
+ More accurate reference counts generally lead to better register allocation.
+
+ It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
+ possibly other information which is used by the register allocators. */
void
-print_rtl_with_bb (outf, rtx_first)
- FILE *outf;
- rtx rtx_first;
+recompute_reg_usage (f)
+ rtx f;
{
- register rtx tmp_rtx;
-
- if (rtx_first == 0)
- fprintf (outf, "(nil)\n");
+ rtx insn;
+ int i, max_reg;
- else
+ /* Clear out the old data. */
+ max_reg = max_reg_num ();
+ for (i = FIRST_PSEUDO_REGISTER; i < max_reg; i++)
{
- int i, bb;
- enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
- int max_uid = get_max_uid ();
- int *start = (int *) alloca (max_uid * sizeof (int));
- int *end = (int *) alloca (max_uid * sizeof (int));
- char *in_bb_p = (char *) alloca (max_uid * sizeof (enum bb_state));
+ REG_N_SETS (i) = 0;
+ REG_N_REFS (i) = 0;
+ }
- for (i = 0; i < max_uid; i++)
+ /* Scan each insn in the chain and count how many times each register is
+ set/used. */
+ loop_depth = 1;
+ for (insn = f; insn; insn = NEXT_INSN (insn))
+ {
+ /* Keep track of loop depth. */
+ if (GET_CODE (insn) == NOTE)
{
- start[i] = end[i] = -1;
- in_bb_p[i] = NOT_IN_BB;
- }
+ /* Look for loop boundaries. */
+ if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
+ loop_depth--;
+ else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
+ loop_depth++;
- for (i = n_basic_blocks-1; i >= 0; i--)
- {
- rtx x;
- start[INSN_UID (basic_block_head[i])] = i;
- end[INSN_UID (basic_block_end[i])] = i;
- for (x = basic_block_head[i]; x != NULL_RTX; x = NEXT_INSN (x))
- {
- in_bb_p[ INSN_UID(x)]
- = (in_bb_p[ INSN_UID(x)] == NOT_IN_BB)
- ? IN_ONE_BB : IN_MULTIPLE_BB;
- if (x == basic_block_end[i])
- break;
- }
+ /* If we have LOOP_DEPTH == 0, there has been a bookkeeping error.
+ Abort now rather than setting register status incorrectly. */
+ if (loop_depth == 0)
+ abort ();
}
-
- for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
+ else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
{
- if ((bb = start[INSN_UID (tmp_rtx)]) >= 0)
- {
- fprintf (outf, ";; Start of basic block %d, registers live:",
- bb);
+ rtx links;
- EXECUTE_IF_SET_IN_REG_SET (basic_block_live_at_start[bb], 0, i,
- {
- fprintf (outf, " %d", i);
- if (i < FIRST_PSEUDO_REGISTER)
- fprintf (outf, " [%s]",
- reg_names[i]);
- });
- putc ('\n', outf);
- }
+ /* This call will increment REG_N_SETS for each SET or CLOBBER
+ of a register in INSN. It will also increment REG_N_REFS
+ by the loop depth for each set of a register in INSN. */
+ count_reg_sets (PATTERN (insn));
- if (in_bb_p[ INSN_UID(tmp_rtx)] == NOT_IN_BB
- && GET_CODE (tmp_rtx) != NOTE
- && GET_CODE (tmp_rtx) != BARRIER)
- fprintf (outf, ";; Insn is not within a basic block\n");
- else if (in_bb_p[ INSN_UID(tmp_rtx)] == IN_MULTIPLE_BB)
- fprintf (outf, ";; Insn is in multiple basic blocks\n");
+ /* count_reg_sets does not detect autoincrement address modes, so
+ detect them here by looking at the notes attached to INSN. */
+ for (links = REG_NOTES (insn); links; links = XEXP (links, 1))
+ {
+ if (REG_NOTE_KIND (links) == REG_INC)
+ /* Count (weighted) references, stores, etc. This counts a
+ register twice if it is modified, but that is correct. */
+ REG_N_SETS (REGNO (XEXP (links, 0)))++;
+ }
- print_rtl_single (outf, tmp_rtx);
+ /* This call will increment REG_N_REFS by the current loop depth for
+ each reference to a register in INSN. */
+ count_reg_references (PATTERN (insn));
- if ((bb = end[INSN_UID (tmp_rtx)]) >= 0)
- fprintf (outf, ";; End of basic block %d\n", bb);
+ /* count_reg_references will not include counts for arguments to
+ function calls, so detect them here by examining the
+ CALL_INSN_FUNCTION_USAGE data. */
+ if (GET_CODE (insn) == CALL_INSN)
+ {
+ rtx note;
- putc ('\n', outf);
+ for (note = CALL_INSN_FUNCTION_USAGE (insn);
+ note;
+ note = XEXP (note, 1))
+ if (GET_CODE (XEXP (note, 0)) == USE)
+ count_reg_references (SET_DEST (XEXP (note, 0)));
+ }
}
}
}
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